FR2528196A1 - APPARATUS FOR PROTECTING COMPUTER PROGRAMS - Google Patents

Abstract

THE INVENTION RELATES TO PROGRAM PROTECTION APPARATUS. IT RELATES TO AN APPARATUS FOR A COMPUTER AND IN WHICH MEMORY 90 SAVES PROGRAM AUTHORIZATION IDENTIFIERS. PROCESSOR 2 RECEIVES THE NAME OF THE PROGRAM CARRIED BY A DISK AND DETERMINES WHETHER THE AUTHORIZATION IDENTIFIER FOR THIS PROGRAM IS CONTAINED IN MEMORY 90. THE DISC CONTAINS A TIMING INDICATOR AND A SENDING DISK INDICATOR FOR DETERMINING THE QUANTITY OF THE DISC. APPLICATION TO THE PROTECTION OF COMPUTER PROGRAMS.

Description

The present invention relates to the field of computers and more

  precisely the processes and devices

  protection of programs incorporated in such computers.

  tors. Program protection is intended to provide authorization for the use of software in a particular computer system. Before a system accepts a computer program, it is desirable that the system provide verification by means of work of

  programsprotectionprocesses, so that the authorization

  Program Definition Is Identified In this specification, the term "program protection" is intended to mean those processes and devices that provide assurance that the computer system only accepts and uses the computer system.

  the appropriately licensed software for that computer.

  The protection of the programs is necessary for various reasons One of the reasons is due to the fact that a

  computer system requires software that is

  particular characteristics which are particularly adapted to

  When a computer program has not been spe-

  cialement adapted to a passage in the computer system,

  the passage of the software can introduce unwanted errors

  The protection of the program is also desirable so that only properly tested programs can

  be used in a computer system.

  Only computer programs having the necessary characteristics and having undergone tests

verification are allowed.

  Another reason for software protection

  is to facilitate its marketing.

  are often licensed for a particular hardware system only In these circumstances, it is necessary to identify whether the computer program

  is allowed for a particular system or not.

  the loading of an unauthorized program must

  reject the program by the computer system.

  Another reason for protection is the

  difference between different versions of programs For example, an original program may differ a lot from new editions of a program containing updates and improvements These new editions may require special hardware features or the payment of a special fee before proper authorization . In addition, computer specialists know that there are other reasons why

  programs is desirable in treatment systems.

data.

  In many computer systems, programs are stored and provided to system users on magnetic media. These are often flexible disks because they are small, lightweight and easily transportable. Disks are very important for commercialization of computer programs Like magnetic disks

  can be easily reproduced in copies and are easily

  can not be changed, they have posed significant problems

protection of programs.

  Various methods of protecting the software have been proposed, especially stored on magnetic disks.

  protection procedures have not given the appropriate flexibility

  authorized uses nor sufficient protection

  against unauthorized use.

  In view of the foregoing considerations, the invention relates to improved methods and apparatus for protecting programs for computer systems.

data processing.

  The invention relates to methods and apparatus

  protection of programs in computer systems.

  The protection apparatus comprises a detection device

  disk drive to generate a program protection signal whenever a magnetic disk has just been loaded for use in the system Each time a disk has just been loaded into the system, it is queried so that his authorization in the system

  If the disk is not self-

  rised, the system does not accept it If it is allowed, it

  is accepted for normal use.

  According to one of the features of the invention, a transmitting disk detector is intended to determine whether a newly introduced disk is a transmitting disk or not The transmitting disks are of two types, blank or not A blank emitter disk has not Authorization identifier for any authorized user system A blank transmitter disk may be authorized for use on any properly authorized system When a transmitting disk is newly loaded

  in the system, the fact that it is blank or not is

  If it is blank, the system works so that it

  loads a system identifier that is allowed on the disk.

  When the identifier has been kept on the disk,

  it is no longer a virgin and becomes a non-virgin transmitter.

  Then, whenever the disk is loaded into the authorization system, it checks whether the disk is authorized

in the system or not.

  When a disc is not a transmitter, it may be an authorized copy of a transmitter whose passage is allowed Whenever a disc is newly

  loaded into the system and that the main detector deter-

  that the disk is not a transmitter, the system checks that the disk is an authorized copy If it is an authorized copy, the system can access the disk

  so that he reads or writes information normally.

  Whenever a particular program must be reached on a disk that is allowed, the program is checked so that its authorization on the system is checked If the program is authorized and the disk also, the system can have access to the disk and the program who

is preserved there.

  As mentioned above, the invention relates to a method and apparatus for protecting programs which facilitate the distribution of authorized programs over

  authorized discs, while preventing the use of

  unauthorized programs and programs.

  Other features and advantages of the

  will become apparent from the following description,

  Referring to the accompanying drawings in which: Figure 1 is a block diagram of a global data processing system according to the invention; FIG. 2 is a schematic perspective view of a disk assembly for driving a flexible disk

  so that data can be read and written during the

  the system of Figure 1; FIG. 3 represents a flexible disk having

  a synchronization indicator and an authorization indicator

sation of a transmitter disk;

  FIG. 4 is a diagram of the times

  both the output signal of an indicator detector of a transmitter disk of Figure 3 used in the assembly of Figure 2; Fig. 5 is a block diagram of a transmitter disk detector used in the system of Fig. 1; and FIG. 6 is a block diagram of a

  authorization circuit for detecting magnetic disks

  allowed in the system of Figure 1.

System as a whole Figure 1

  As shown in Figure 1, unit 2 of treatment

  This includes a common address line 17, a common data line 18, and control lines 19. The processor 2 also receives an interrupt signal. INIT of a first level and a VIR interrupt signal of a second level of the unit

  common line 5-0 These interrupt signals are

  by the program protection mechanism.

  FIG. 1 indicates that a plurality of common line units 4 and 5-0 ,, 5-3 are connected to the common line 22. For example, the unit 4 is a direct access memory which acts as a main memory for the data processing system of FIG. 1 The units -0 to 5-3 comprise, for example, input-output devices such as keyboards, flexible disks and hard disk storage devices, parallel devices of FIG. input-output, processing units and

other types of units.

  The common line unit 5-0 of FIG. 1 comprises a flexible disk device 25 and a conventional control circuit providing the interface of the device.

with the system of Figure 1.

  Device 25 and unit 5-0 are used

  for loading computer programs into the system.

  This one is intended to only accept discs

  and authorized programs for the system of Figure 1.

  In FIG. 1, a logic unit with programmable arrangements 88 is incorporated in the unit 6. The unit 88

  receive each address of the common line 17 and, consequently,

  quence and according to a predetermined algorithm and / or a determined coding, gives an encoded output signal transmitted by the common line 18 of data The signal of this line is a system identifier This identifier is kept in an authorization data field d a blank floppy disk so that the system can then read the

disk.

  Figure 2 shows schematically a flexible disk drive assembly forming part of the device of Figure 1 The flexible disk 26 indicated in broken lines can move freely in its envelope 27 This and the disc 26 are inserted together in the direction of the arrow 24 in the assembly of Figure 2 The door 30 must be open for the introduction of the sleeve 27 and the disc 26 in the assembly of Figure 2, in the direction of the arrow 21 and around the pivot 20 so

  sufficient space allows this introduction or

  removing the disk 26 and the envelope 27.

  The whole of Figure 2 includes a device

  detection device in the form of a switch 31 intended to de-

  detect when a flexible disk has just been introduced into the system When the door 30 is raised, the switch 31 transmits a program protection signal PP by

  line 44 This signal indicates that door 30 was

  green and therefore an unauthorized disc may have been introduced into the device 25 The protection signal

  programs triggers a query intended to de-

  end if the introduced disc is allowed or not.

  When the door 30 is raised, the linkage 32 causes the removal of the member 39 upwards by control of the assembly 41 The lifting of the member 39 when the door 30 is open causes the removal of the tip 42 of the central indicator 16 of the disk 26 The tip 42 is introduced so that it can rotate relative to the member 39 When it is in contact in the indicator 16, it cooperates with a driving member formed at the end

  of the drive shaft of the motor device 29.

  The latter, through the shaft 15 and the end

  42, lock disc 26 and drive it clockwise.

  A magnetic head 11 reads the data on the disk 26

  and writes on this disc The head 11 is moved in trans-

  by the head drive assembly 28 The head

  11 is disposed above an opening formed in the

  veloppe 27 and thus has direct access to the surface of the disc

that 26.

  A hole 10 is formed in the envelope 27 at a

  predetermined radial position so that a sync track

  disk 26 is exposed as indicated by the

  3, the timing flag 35 is shown

  in the synchronization track in radial position

  The indicator 35 is advantageously a hole, but it can be any other type.

indicator.

  The envelope has two parts, one above and one below the disk 26 of Figure 2 The hole 10 passes through the upper and lower parts of

  the envelope so that when indicator 35 is

  on the 10th hole, a beam of light passes totally

  through the envelope 27 and the indicator 35 without being

  broken. In FIG. 2, an optical detector comprising a light source 34 and a light detector 33 is placed in alignment with the hole 10. The detector 33 detects an indicator such as the synchronization indicator 35 formed in the disk 26 when the the indicator is in front of the axis 8 of the detector light 33 The synchronization mark comes once per turn in front of the window 10 and the axis 8 and is detected once by

  The mark 35 is used for

  classic way of synchronizing reading and

  writing data from the magnetic disk 26.

  Since the two indicators 35 and 36 do not appear simultaneously in the aperture 10, the transmitter disk can be easily detected.

  embodiment, the envelope 27 has notches 94 and 95 des-

  to indicate that the disk is a transmitter The notches 94 are of a standard type intended to indicate a disk

passive memory only.

  Transmitter disk FIG. 3 According to the invention and as indicated in FIG.

  3, a second indicator 36 is placed in the sync track.

  chronization at the same radial distance as the indicator

  The indicator 36 is a hole in the example considered.

  However, any type of indicator is suitable. Thus, when the disk 26 of FIG. 3 is loaded in the assembly of FIG. 2, the two indicators 35 and 36 come together

  once per turn in front of the opening 10 and the axis 8.

  The detector 33 detects the presence of the indicators and 36 and consequently creates an output pulse for

  each indicator, once per turn.

  As shown in Figure 3, the angular difference

  D of indicator 36 in relation to the indicator 35 deter-

  undermines the time lag of the signal detected for the in-

  Dicator 35 and the signal detected for indicator 36 This gap "D" is chosen so that it has a determined value

  indicating that the disk 26 is a transmitter When the

  34 is at a location other than that corresponding to a deviation D or is not present at all, the disc

  26 is not recognized as an issuer.

  FIG. 4 shows a waveform of the output signal of the detector 33 Thus, the pulses at time t1, t3, t5 and t7 are representative of the pulses due to the detection of the indicator 35 by the detector 33 The pulses t 2, t 4, t 6 and t 8 are representative of pulses due to the detection of the indicator 36 by the detector 33 The time t (D) between the pulses t 1 and t 2 is proportional at the angular spacing D of the indicators and 36 In the example described, the indicator 36 is located

  in a quarter of a turn that is to say that D is less than 90.

  Figure 5 shows a main detector comprising the optical detector 33 The waveform of Figure 4 is representative of the signal of the line 59

  last, connected to detector 33, joins a first

  The signal from the gate 51 is the signal RESET which reaches the reset input of the counter C, which is the signal of the output Q of a gate 50. last is controlled by a CLK / X signal so that it counts continuously from a

  preset number, up to the maximum number before auto-

  so that it continues to count.

  The parallel output signal of the counter 45

  reaches a first input of a comparator 47

  This comparator 47 compares the contents of the register 46

  to that of a counter 45 The number of the register 46 is chosen

  if so that it represents the difference D between the indicators 36 and 35 The signal of the indicator 35 resets the counter 45 to zero and the clock control of the counter 45 is such

  that, in the case of a transmitting disk, the number of

  45 is equal to the number in register 46 when the

  dicator 36 is detected by the detector 33.

  The rocker 50 is controlled by the clock signal CLK and stores the signal of the comparator 47. The clock signal transmitted to the counter 45 is divided by 4 in a suitable conventional circuit 53 so that a misregistration between the numbers of register 46 and counter 45 can not appear Thus, it is certain that,

  when the comparator 47 transmits a level signal lo-

  a comparison between the numbers of the counter and register 45 and 46, this signal is

in the rocker 50.

  When the comparison is detected and trans-

  switching to the rocker 50, the door 51 is no longer prepared so that a pulse detected by the line 59 and from the detector 33 does not reset the counter 45 When the rocker 50 has not been triggered for storage

  of a logical level signal at its output Q and a

  zero logic level signal at its output Q the Q output signal is in state 1 and thus prepares the opening

  When the door is prepared, any impulse

  sion of line 59 resets counter 45 to zero.

  The presence of a positive comparison signal comparator 47, stored in the rocker 50, and a

  pulse in line 59 is detected by the NAND gate.

  AND 54 and controls the rocker 55 by the clock input.

  The latter receives a signal 1 at its input D and keeps it at its output Q under the control of the clock signal Le 1 kept in the rocker 55 is transmitted to the rocker

  56 by a transition of the output signal of an AND gate 49.

  This receives signals from the detector 33 and a decoder 48. The decoder 48 is set to recognize a number representing a complete revolution of the disk 26, in the counter 45 when the latter is reset by the pulse 35 transmitted by the gate 51, the decoder 48, if it has not been restored, reaches a number represented by a complete revolution of the disk 26 and transmits a signal 1 to the AND gate 49 The simultaneous appearance of the number of the decoder 48 and a pulse transmitted by the decoder 33 by the line, 59 transmits the contents of the rocker 55 to the rocker 56 so that the signal emitter appears in the line 58 in the form of a logic signal 1 When this signal is transmitted in the rocker 56, the rocker 55 is restored

by the signal from the door 49.

  The rocker 56 is reestablished by the signal from the gate 57. The latter transmits a signal at its output when, at the moment when the NAND gate 51 transmits a signal 0 for resetting the counter 45, the gate 49 does not indicate

  not that the decoder 48 has transmitted an output signal.

  The operation of the primary detection circuit

  FIG. 5 is the following when the disk 26 of FIG. 3 is a transmitter disk. When the pulse t1 of FIG. 4 from the indicator 3-5 causes the transmission of a signal via the line 59, the signal of the rocker 50, transmitted to the gate 51, is in the state Thus,

  the signal from the gate 51 is detected as being an O

  The counter 45 then continues to count the clock pulses. A number representing the position of the indicator 36 is loaded into the register 46 when the indicator 36 is in the detection position by the detector 33 and gives the signal. At pulse t 2 of FIG. 4, the comparator 47 transmits a signal 1 to the rocker 50 whose Q output is at zero Ce O transmitted to the gate 51 prevents the signals of the gate 41 under the control of the gate from being taken into consideration. impulse t 2 of line 59 if

  although the counter 45 is not reset by the pulse

sion t 2.

  However, the pulse t 2 is transmitted to the NAND gate 54 with a 1 of the rocker 50 and shows that

  the signal from the gate 54 is an O causing the transmission

  This signal 1 is kept in this rocker until the counter 45 has advanced to the number of a complete cycle indicated by the detector.

  48 This number of the complete cycle of the detector 48 and the impulse

  sion t 3 of the second round of record 26 at the same time as the

  indicator 35 on the detector 33 provoke

  the signal transmission 1 of the rocker 55 in the latch

  At this time, the TRANSMITTER signal of line 58 indicates that the disk 26 is a transmitter. The rocker 56 is not re-established by the gate 57 as long as a transmitter disk

  26 is in the whole of Figure 2.

  We consider the operation of the circuit of

  FIG. 5 when the disc 26 is not a disc emitting

  At the moment when the impulse tl of indicator 35 appears

  the rocker 50 is again controlled so that its output Q is 1 so that the signal of the gate 51 is

  considered to reset counter 45 to zero if the indi-

  34 is not present or is present at a location other than the distance D, the comparator 47 transmits at most a signal to the rocker 50 at a time which does not correspond to a pulse of the line 59.

  therefore never transmit a signal 1 of the output Q of the bascu-

their 55.

  If a second indicator 36 is placed for example with a difference other than D, the operation of the circuit of FIG. 5 is the following. Each of the pulses t 1, t 2, t 3, t 8 of the line 59 causes the opening of the gate 51 and the passage of the signal RESET which ensures the reset of the counter 45 Thus, the counter 45 does not reach the number of the complete cycle and the decoder 48 does not allow the transmission of a signal to the gate 49 Thus, the line does not transmit a cycle synchronization signal The signal of this line remains at zero so that with the

  signal from gate 51, it ensures the restoration of the

  56 so that the TRANSMITTER signal of line 58

  can not be transmitted The absence of the synchronization signal

  cycle once a turn indicates that a disc emits

  unauthorized transmitter is present in the system.

  When the disc 26 has a single indicator 35

  synchronization, the operation of the circuit of the

  Figure 5 is the following Whenever a signal tl, t 3,

  t 5 and t 7 appears in line 59, door 51 is

  green and transmits the signal RESET which puts the counter 45

  Zero impulses t 2, t 4, t 6 and tg are not pre-

  since the counter 45 is reset only once per revolution, and the decoder 48 transmits a signal at the same time that the signals can come from the line 59 of the detector 33. As a result, the door 49 does not open. only once per cycle and transmits the synchronization signal

cycle through line 60.

  When the number of the counter 45 corresponds to the main number of the register 46, the rocker 50 is controlled so that it retains a signal 1 However, since there is no corresponding pulse in the line 59 when the rocker 50 is controlled, the door 51 is not open and the door 54 does not therefore In the absence of a synchronization pulse of the line 59 corresponding to the main indicator 36, the signal of the comparator 47 prevents the reset of the counter 45 and prevents the control of the rocker 55 to maintain a signal 1 The cycle synchronization signal of the line 60 constantly restores the rockers 55 and 56 under these conditions The transmission of the cycle synchronization signal of the line 60 when 'No TRANSMITTER signal is transmitted by line 58, indicates that disk 26 can

  be an authorized copy of a transmitting disk.

  The decoder 48 is adjusted so that it

  hold a number representing the number of elementary slots existing when the disk 26 makes a complete revolution In one example, the decoder 48 is set to 252

  and the counter 45 is an 8-bit binary counter.

  cooked 53 division by X allows selection of quantity

  X so that 252 clock signals arrive at the

  45 for each revolution of the disk 26 In the example o the displacement D is about 600 and the decoder 48 is

  set at 252, register 46 retains a number equal to 42.

  In general, the dimensions of the indica-

  35 and 36 are chosen at a value greater than

  dimension represented by a single number of the counter 45.

  Thus, the actual diameter of the indicator 36 is chosen so that its location is in a position shown

  by the numbers 41, 42 and 43 of the counter 45 As the frequency

  If the timer of the rocker 50 is X times greater than that of the counter 45, the rocker 50 can not miss the detection of the indicator 36.

  indicators 35 and 36, the number representing a com-

  plet (represented by the number decoded in the decoder 48) and the location of the main indicator 36 relative to the synchronization indicator 35 (contents of the register 46) are parameters which can be determined according to the frequency of the signal CLK clock and angular velocity

of the disc 26.

  Authorization circuit Figure 6 Figure 6 shows further details of a

  authorization circuit This circuit of Figure 6 is

  part of the assembly 5-0 of Figure 1 This last

  a flexible disk device 25 and the entire circuit

  it is necessary to couple this device 25 to the common line 22. Such a control circuit is conventional and

  includes a number of known elements.

  6, the unit 5-0 comprises a data register 72 which exchanges the data with the disk device 73. The latter comprises the training unit of FIG. 2. The register 73 receives the data from the disk.

  26 through the buffer circuit 87 and the multi-

  plexers 70 and 71 The data are stored in the regis-

  72 when it is prepared by the load signal-

  registering data from a circuit 65 of

command and sequence.

  The location of reading and writing of

  The address 26 of the address register of the address register 65 is determined by the address register 69. It can store an address under the control of the address register load signal from the circuit 65. The address stored in the register 69 can also be read of the common line

* 17 which is part of the common line 22 of Figure 1.

  The high order address bits of the line 17 reach the decoder 66 to indicate when an address space of the unit 5-0 has been addressed. The lower order bits of the common line 17 reach at an entrance

  of the multiplexer 68 so that they are loaded into the reg-is-

  The other input of the multiplexer 68 receives the signal from the code address generator 67. The latter retains the addresses of the locations of the system identifier field and the program name field on the disk 26. address is a passive memory, a counter or other device that transmits addresses successively It is reset by the start address when the reset signal of the OR gate 86 is present The generator 87 progresses to a new address

  under control of the AS signal of the circuit 65.

  The multiplexer 68 selects the address of the generator

  When the INIT initialization signal is transmitted by the toggle switch 82, the common line 18 exchanges the data with the unit 5-0. In FIG. 6, the common line transmits an input signal to the multiplexer 70. then transmits an input signal to the multiplexer 71 which

  itself transmits an input signal to the data register 72.

  born. The data transmitted by the common line 18 comes from the buffer 87 which receives the data from the register 72 The multiplexer 70 receives a second signal taken from the data from the disk 26 in a disk device 73 The data is taken from the common line 18 so that they are transmitted to the multiplexer 71 and the data register 72 when the write signal W of the circuit 65 is present When the signal W is not

  present, the multiplexer 70 selects the data of the dis-

  positive 73, transmitted by the common line 61.

  The data of the common line 18 is also transmitted to the system identifier register 74 and the program authorization register 92. The register 74 stores the data from the line 18 when it is prepared by the AND gate signal. 89 which receives the signals INIT and VIR A system identifier, kept in the register 74, is chosen by the multiplexer 71 so that it is kept in the register 72 and written on the

  The selection for the multiplexer 71 takes place when

  that the signal indicating a blank disk VIR, from the rocker 78, is present In the absence of the signal VIR,

  the multiplexer 71 selects the output signal of the multi-

  plexeur 70 so that it is kept in the register 72.

  The system identifier from the register 74 is also selected by the multiplexer 76 and arrives at an input of the comparator 64 when the blank test signal

  TEST VIR is not present at the Q output of the rocker 80.

  When this signal is present, the blank identifier is selected in the register 75 by the multiplexer 76 and forms an input signal of the comparator 84.

  the latter is transmitted by the data register 72.

  The comparator 64 has the function of comparing

  the contents of the register 72 to a virgin identifier

  from the register 75 at a time when the signal TEST VIR has been determined as present, and at other times, it compares the contents of the register 72 to the identifier of the register 74. When the contents are identical, the signal

  comparator 64 can prepare AND gates 84 and 85.

  The OR gate 86 of FIG. 6 receives the signal PP from the line 44 coming from the sensor 31 of FIG. 2, and is schematically represented as being part of the device 73 of FIG. 6. This gate 86 also receives a signal from FIG. SYCLR system erase which is present for example every time the system of Figure 1 is powered up This signal also reaches the other times when the states of the registers and other memory devices ask questions Every time the door 86 is open and its output signal is present, the rocker 81 is re-established so that its output Q is zero

and its Q output to one.

  After the operation of the circuit of FIG. 6, when the disk present in the set of FIG. 2 is determined to be an authorized disk, the disk authorization signal permits the opening of the gate 91 When the disk program 26 is authorized for the system, the signal from register 92 opens the door 91

  signal from this door then allows the tipper 81 to

  Serve a signal 1 at its output Q and a signal O at output Q Whenever the rocker 81 has been re-established, for example when the gate 30 of FIG. 2 has been opened so that the signal PP of FIG. , the door 62 is prepared by a signal 1 of the output Q of the

  Each time the decoder 66 detects the address

  5-0 of the unit (see Figure 1) after the door 62 has been prepared, the rocker 82 is controlled so that it maintains a signal 1 at its Q exit, so it valid

  the presence of the signal INIT This presence-causes the deter-

  6 by the circuit of the fact that the disk 26 is authorized or not The signal INIT is transmitted in the form of an interrupt signal to the processor of FIG.

1 by 'Line 38.

  In addition, when the INIT signal is present, the multiplexer 68 selects the code address from the generator 67 to keep it in the address register 69. The INIT signal is also transmitted to the circuit.

  65 to control the transmission of the output signals

  of this circuit, causing the authorization verification functions to be performed by the apparatus of FIG. 6. The signal INIT also reaches the gate 83 which also receives, at another input, the signal TRANSMIT from

  of the detector 43 of FIG.

  The trigger is triggered by the rocker 82 in the presence of the INIT signal, the disk 26 is a transmitter disk as indicated by the presence of the TRANSMITTER signal, the gate 83 then being open so that it transmits the signal 1 to the Q output of the rocker 80 This output Q, when

  transmits such a signal, forms the signal TEST VIR which pro-

  check that disk 26 is a disk

  than a blank transmitter. The present signal TEST VIR prepares the gate 84 whose other input is connected to the output of the comparator 64 The present signal TEST VIR causes the transmission by the multiplexer 76 of the blank identifier signal of the register 75 to an input of the comparator 64 If the content of the register 72 corresponds to the blank identifier, the signal of the comparator 64 prepares the gate 84 so that the signal VIR is determined as present at the output Q

  when this VIR signal is present indi-

  when the transmitter disk of the assembly of FIG. 2 is blank, the multiplexer 71 allows the storage of the identifier of the register 74 in the register 72 so that

  that the identifier is written on the disk 26.

  The system identifier has already been loaded

  in register 74 following the interruption of the pro-

  cessor 2 caused by the presence of the INIT signal in line 38 When the system identifier is

  stored in the register 72 by control of the validity signal

  LDDR from the circuit 65, the rocker 77 is

  ordered to keep the signal TEST VIR Simultané

  The presence of the LDDR signal restores the empty switch 78. When the blank identifier is kept in the register 72, a write signal is controlled by

  the presence of the signal W coming from the circuit 65 The identification

  blank is written on disk 26 at the special address

  cified by the address register 69.

  Then, as the VIR signal is not present,

  the multiplexer 71 selects the output signal of the multi-

  plexeur 70 to transmit it to the data register 72.

  The circuit 65 then causes a reading cycle by means of

  r-line signal which causes the system identifier of the disk device 73 to read and

  its conservation in the data register 72.

  When the rocker 77 is controlled by the

  LDDR, it presents a signal at its output Q allowing the restoration of the rocker 80 and thus removing the

  signal TEST VIR The multiplexer 76 thus transmits the identity

  register system 74 at an entry of the compa-

  64 with the identifier of the register 72 already read on the disk 26 When the comparator 64 validates its signal

  exit 85 was prepared at the time of the reinstatement.

  the rocker 80 so that the rocker 79 is

  This signal controls the rocker 81 and allows the presence of the authorization signal. This signal re-establishes the rocker 82

  and cancels the INIT signal while restoring the

  77 and 79 When the INIT signal is canceled, the

  interrupted line 38 is deleted and the cir-

  Fig. 6 thus indicates that disc 26 is

  When the INIT signal is canceled, the multiplexer 68 directly connects the common line 17 to the register 69 and the common line 18 to the common line 17.

register 72.

  The control and sequence circuit 65 of FIG. 6 is a conventional sequential logic device that operates in a known manner and transmits a number of sequential signals. These include a signal

  LDAR for validating register 69, a LDDR signal for validating

  register 72, the control signal W of the writing

  the signal R controlling a read operation of the contents of the disk 26 in the register 72, and an AS signal for advancing the address generator 67. for the reading and writing of data when the signal INIT has not been determined as present However, in the presence of the signal INIT, the

  circuit 65 transmits a sequence of output signals per-

  putting the implementation of the pro-

  grams, as described in detail in the following table:

LDAR = (INIT * T 1)

+ AD Normal Load * INIT

R = (TEST VIR * INIT * T 2)

+ (TEST VIR * VIR * INIT * T 5)

+ (VIR * T 6 * INIT)

+ llire normall * INIT

W = (VIR * INIT * LDDR * T 4)

+ lecrire normall * INIT

LDDR = (VIR * INIT * T 3)

  + (R * IN It J * (T 2 + T 5 + T 6) + load DA normall * INIT

  AS = T 1 + T 2 + T 3 + T 4 + T 5 + T 6

  In the table, the asterisk "*" represents

  an intersection logical operation and the symbol "+" represents

  sense a logical operation meeting On the board, the last line of each of the equations except the signal

  AS, represents the normal operation when the initial signal

  INIT tuning has not been determined as present. All other lines represent the operation of the sequence circuit when the INIT signal has been determined as present. Disk Authorization Operation

  The operation of the circuit is now described.

  of FIG. 6 when the door 30 has been opened and when a transmitter disk 26 has been placed in the assembly of FIG. 2 When the door 30 is open, the signal

  PP is received by the door 86 and restores the rocker 81.

  This prepares the door 62 when the system of the

  1 addresses the 5-0 unit, and the decoder 66 causes the

  door 62 so that the rocker 82 is

  In this moment, the signal LDAR, as indicated by the table, is transmitted to T1 and loads the address register of the content of the coded address generator 67. The address of the generator is the address. The INIT signal causes an interruption of the processor 2 which in turn causes the identifier to be loaded into the generator 74 of FIG. 6 which is prepared to receive.

  the identifier given the presence of the signal INIT.

  The signals INIT and EMETTEUR are present and

  open the door 83 so that the signal TEST VIR is pre-

  The latter, in the presence of the signal INIT as indicated by the table, causes the appearance of the signal R at time T 2 so that the content of the disk 26 at the address specified by the register 69 is read. 26 is

  kept in register 72 through the multi-

  plexeurs 70 and 71 The presence of the signal R at the time T 2 in the presence of the signal INIT as indicated in the table causes the presence of the signal LDDR at the time T 2 and allows the register 72 to keep the data of the disk 26 In the presence of

  signal TEST VIR, the multiplexer 76 selects the identifier

  in the register 75 and compares it to the data of the register 72 If the two elements of the comparison are identical, the comparator 64 transmits a signal which causes

  the appearance of the signal VIR at the output of the rocker 78.

  When the registers 72 and 75 do not have the same content, the comparator 64 has no signal present at its output

and the VIR signal does not appear.

  In the example in which the disk 26 is a blank transmitter, the system identifier from the register 74 is loaded into the register 72. The latter is loaded by the signal LDDR which, as indicated in the table, is present at the time T. 3 when the two signals VIR and INIT are present When the signal LDDR at T 3 causes the conservation of the identifier in the register 72,

  signal W is present at time T 4 as indicated by

  bleau and ensures the writing of the contents of register 72 on

  the disk 26 The loading of the register 72 by the dentification

  in the presence of the signal LDDR at T 3 cancels the signal VIR.

  Under these conditions, the signal R is present at the time T 5 and causes the retention of the identifier read on the disk 26 in the register 72 The LDDR signal is present at time T 6 and causes the retention of data read

  on the disk in the register 72.

  At that moment, the contents of register 74 are

  the contents of the identifier of the register 72 taken from the disk and, in the absence of an error, the result is

  positive The door 85 is open and transmits the signal of

  When the program authorization register is also established, the door 91 opens and allows the transmission of the authorization signal by the toggle switch 81. This signal cancels the INIT signal and the disc 26. is ready for normal access by

the system of Figure 1.

  In the example described in which the disk is not a blank disk and the VIR signal is never transmitted by the rocker 78, the register identifier 74 is never loaded into the register 72 and is not written on

the disk 26.

  The operation of the circuit of FIG. 6 is now considered when the transmitter disk is not a blank disk. When the comparator 64 determines that the contents of the register 72 differ from those of the register, the VIR signal is not present. time T 2, placing the data in the register 72, restores the rocker 77 and cancels the signal TEST VIR after the next clock pulse CLK When the two signals VIR and TEST VIR are canceled, the multiplexer 76 is switched so that it selects the output signal of the register 74 so that it is then compared to the contents of the register 72 If the result is positive, the door 85 is prepared

  and the rocker 79 progresses so that the authorization signal

  If the program is also self-

  risé, this last signal prepares the door 91 and command

  the rocker 81 which ensures the transmission of the automatic signal.

  In the latter case, the interrupt 38 is deleted and the unit 5-0 of the

  Figure 1 can not be used in a general way.

  This operation takes place in the case of a non-blank transmitter disk. Such a disk is of a type that has already been auto-

  ris & 'for its use in the system of Figure 1.

  The operation of the circuit of FIG. 6, when the disk 26 is not a transmitting disk, is as follows. When the disk is not a transmitter, the TRANSMITTER signal is canceled and, consequently, the signal of the gate 83 is not present Thus, the signals TEST VIR and VIR are not present A read operation during the time T 5 thus ensures the reading of the data of the address specified by the register 69 The data of the location addressed on the disk 26 If the contents of the latter, taken from the disk 26, are identical to that of the register 74, the comparator 64 transmits

  its output signal and prepares the gate 85 which is com-

  sent via the toggle switch so that the disk authorization signal is present, this signal allowing the transmission of the authorization signal and the canceling of the INIT signal in the case of an authorized program. In these conditions, the comparator 64 transmitting a signal

  1, the disk 26 is an authorized copy of a transmitter

  When the contents of the registers 72 and 74 differ, the output signal of the comparator is not present if

  although none of the disc and other authorization

  torisation is present The signal INIT remains present and the interruption of the line 38 is not deleted The processor 2 recognizes the moment when the interruption of the line 38 is not suppressed for a sufficient period

  and then it transmits a protection of pro-

  gram identifying the disc introduced in the set 5-

0 as unauthorized.

  In the system of Figure 1, the processor

  2 detects the interruption of the line 38 in a conventional manner.

  The address of the common line unit 5-0 which pro-

  where the interruption of the line 38 has been transmitted by the processor 2 via the common line 17 When the logic unit 88 of programmable settings

  of Figure 1 is validated by the signal VIR, it trans-

  The data signals of this line are transmitted to the unit -0 and stored in the system identifier register 74 under the control of the signal of the gate 89, the

as previously indicated.

  In the example described, the logical unit 88 is

  addressed by a single address sequence However, several

  sequential addressing addresses of the unit 88

  may be necessary before the appearance of the

  This unit can be relied upon 88 The use of several

  sequential addresses significantly increase

  protection against attempts to break the

me protection.

  The programmable logic unit 88 transmits the identification

  system identifier that is used to determine whether the disk is allowed or not In the case of a blank emitter disk, the unit 88 transmits the system identifier that is kept on the disk so that it forms

  a non-blank transmitter disk and thus allows the use of

  The logic unit 88 can perform any desired function on the address transmitted by the common line 17 so that the system identifier is transmitted by the common line 18 In the system of FIG. 1 of this disk and its copies. an example, the system of line 18 can

  be identical to the address in line 17 so that the identification

  is simply the address of logical unit 88.

  Authorized implementation of the program In Figure 1, the permanent memory 90 is connected so that it is addressed by the common line

  17 and transmits output signals through the line com

  The memory 90 is a device which can be

  se bits transmitted by the common line 17 so that

  the information in line 18 is retained or that the information

  line 18 is read, depending on the status of the signal

  VIR In the presence of this signal, the memory receives informa-

  line 18 and keep them at the addressed location.

  When the VIR signal is not present, the memory 90 can only operate in read mode and transmit the data to line 18 The permanent memory 90 retains this information even when the system of FIG. is

  more powered, and is then turned back on.

  The memory 90 is addressed for reading so that the authorization of the program contained on the disk for the system of FIG. 1 is determined. In one example, the memory 90 has an 8-bit program name field allowing the authorization of the use in the system of Figure 1 of a number of different programs up to 256 The high order address bits of the line

  17 are decoded for the selection of the memory 90 of

  classic and the 8 lower order bits of the address

  correspond to the possible names of the programs of the disc.

  The memory 90 is therefore a memory of authorized programs that retain an indication for each program that

is allowed, up to a maximum.

  When the signal INIT is detected by the processor 2 and provided that the signal VIR is present, the processor 2 first addresses the unit 88 of FIG. 1 so that it has access to the identifier of the system.

  in the register 74 of Figure 6 as previously indicated.

  The processor 2 then controls the signal VIR and, when it is present, it updates the permanent memory at the appropriate moment This suitable moment appears after the signal T 6 If the signal VIR is present, the processor 2 executes the operation The lower order address bits form the program name taken from the disk 26. A bit in state 1 is stored in the memory.

  permanent memory at the address of the program determined

  that the name of the program is taken from register 72 to be

  transmitted to the blank transmitter disk.

  After the write operation on a blank transmitter disk (in the presence of the VIR signal) or directly in the case of any non-blank disk (absence of the VIR signal), the memory 90 is read using the name of program corresponding to the lower order address The single bit of data 1 or O is transmitted by bit 9 of line 18 and is stored in the program authorization register 92 so that it transmits the authorization signal If the program is properly authorized in the system, the register 92 retains a signal 1 and thus prepares the door 91, when the authorization signal

  disc is formed by the rocker 79 of FIG.

  If the disk is not allowed, ie in the absence of the disk authorization signal, or if the program is not authorized, ie if the authorization signal of register 92 program is not present, door 91 is not open and the disk authorization signal

program is not present.

  If the disc is not allowed or if the program

  is not, the rocker 81 is not set to 1 and does not transmit

  does not put the authorization signal In the absence of this signal, the rocker 82 is not restored and the signal INIT remains present as interrupt signal of the processor 2 in the line 38 If the INIT signal is not suppressed after a predetermined time, the processor recognizes that an exception to program protection exists and continues processing without allowing access to disk 16 by

  normal read and write operations.

  It is understood that the invention has not been

  as a preferred example and that any technical equivalence may be

  constituent elements without departing from its scope.

Claims (7)

  A program protection apparatus for a computer system, itself for receiving programs from a disk placed in a disk device, said apparatus being characterized in that it comprises:   a detection apparatus (31) for transmitting   setting a program protection signal (PP) indicating when a disk is to be polled so that permission to use that disk in that system is determined,   an authorization device controlled by the.   program protection signal (PP) and intended   manage the disk, this authorization device comprising:   a register (74) for keeping an identity   system, a device (33) for reading data from a predetermined field of the disk, and a comparator (64) for comparing   data from the disk to the system identifier and to   put an authorization signal when the data-autos   the disk drive and the system identifier are identi-   ticks. Apparatus according to claim 1, characterized in that the authorization device further comprises a main detector (43) for transmitting a main signal when the disc is a transmitter,   a device (75) for transmitting an identity   blank printer, a device for causing playback, data of the disk in the predetermined field of the disk following the main signal, and a comparator (64) of the data of the disk with the blank identifier for transmitting a signal blank when the disk data and the identifier virgin are identical.   3 Apparatus according to claim 2, characterized in that it comprises: a device (73) controlled by the blank signal and intended to write the identifier of the system in the   predetermined field of the disc so that the disc come from a non-blank transmitter.   4 Apparatus according to claim 3, characterized in that it further comprises a generator (6) for forming the identifier of the system following the signal   blank, and a device for the conservation of the identifica-   system in the system identifier register.   tem. Apparatus according to claim 4, characterized in that the generator (6) comprises a logic circuit   (88) with programmable arrangements for creating the identification   the system according to the address used to   the addressing of the disk drive by the system.   Apparatus according to claim 5, characterized   in that the transmitter disk <26) has a synchronization track   comprising a synchronization indicator (35) and a main indicator (36) angularly offset from the synchronization indicator, and the main detector (33) includes a gap detection device   angle of the main indicator in relation to the indica-   synchronizer and a device for determining the correspondence of this deviation with the deviation of a transmitter disk. Apparatus according to claim 1, characterized in that it further comprises a device (5-0) for transmitting an initialization signal following the program protection signal (PP) and for preventing the operation of the program. disk device for normal reading and writing of information until the creation of the authorization signal.   8 Apparatus according to claim 1, characterized in that it comprises:   a memory (90) for storing identi-   Program Authorization Factors Identifying Programs   grams allowed in the system, a device for reading the name of a program carried by the disk, and a device (2) controlled by that name and intended for   determine whether the program carried by the disc has an identical   authorizing authorizer incorporated in the authorization   program. Apparatus according to claim 2, characterized in that it comprises:   a memory (90) for storing identi-   Program Authorization Factors Identifying Programs   grams allowed in the system, a device for reading the name of a program carried by the disk, and a device (2) controlled by that name and intended for   determine whether the program carried by the disc has an identical   Authorization tester incorporated into the auto-memory program implementation.   Apparatus according to claim 9, characterized in that the program authorization memory is a   permanent memory (90) which retains the status of the identifica-   program authorization authorities when feeding is interrupted or restored.   Apparatus according to claim 9, characterized in that the detection device comprises a device for addressing the program authorization memory (90).   using the program name so that an identifier of   program override corresponding to the name of the program be obtained.   A program protection apparatus for a computer system itself for receiving computer programs from a floppy disk, characterized in that it comprises: a disk detection apparatus (31) for detecting a introducing a disk into the system,   a device generating an initialization signal   tion to cause a check whether the disk being put in place is an authorized disk or not, a device (33) for detecting the tracks of synchronization of the disk and for detecting the presence   an emitter disk indicator (36) for transmitting   put a main signal when the disc is a transmitter, an interrogator of a transmitter disc (26) which has just been placed in the system, to determine whether the disc is a blank disc or not, a device for storing a system identifier on a blank transmitter disk, and a device for verifying the identifiers stored for the system, on disks that are   put in place to transmit an authorization signal.   allowing normal disk access through the system   when the disk retains the system identifier.