GB2136618A - Data recording and storage arrangement - Google Patents

Abstract

A card 12 is provided on at least one side with one or more strips of magnetic material containing a plurality of tracks of recorded data. The data is read from or written on to the magnetic material using a device which feeds the card past a recording/reproducing head. Preferably, the data is read/recorded in a single pass using a multi-track head and buffer storage. Alternatively, the head may be indexed in a direction transverse to the direction of movement of the card to read/write data in different tracks. In an alternative embodiment the card is held stationary and the head moves. <IMAGE>

Description

SPECIFICATION Data recording and storage arrangement The present invention relates to a data recording and storage device for use with a computer.

In computer technology three basic data recording and storage peripheral systems are used; solid state ROM, tape and disc (either floppy or rigid), the latter being divided into formatted or sectored discs. In home computer work and small office machines, it is often convenient to use tape in the form of a standard 'C' cassette using a perfectly standard tape recorder/player. This has the advantage of using easily obtainable materials in conjunction with wellestablished hardware systems, but has the disadvantage that, in the event several discrete programmes are required to be logged, location of the required data and retrieval times are lengthy since the computer will have to search, possibly, the whole length of the tape before locating the required data. In small business use this is time-wasting for both the user and the computer.

The disc system has the advantage that discs occupy very little space, are available in a number of sizes according to data loading requirements and, therefore, if a small amount of data is required to be logged a small disc may be used, the discs filled in conventional fashion and the data abstracted quickly. The disadvantage of the disc system is that, as yet, disc drives are expensive and, in relation to the home computer, cost almost as much as the basic computer.

In the invention described below, an attempt is made to overcome the disadvantage of the tape and disc system by using a system of electro-magnetic recording in conjunction with a card which conveniently may be 6" x 4" and which is provided, at least on one side with a coating of recording material e.g.

ferrite. One surface of the card is coated and the uncoated side may be used for hand-written or typed information about the data stored on the ferrite coated side.

The characteristics of a ferrite coating are similar to those of a conventional recording tape and one form of the invention data can be recorded using MFM system (Modified Frequency Modulation).

The apparatus for using the cards can vary from a "read-only" device utilising a coating in the form of a single strip on the back of the card in the same manner as used on credit and cash cards. A more sophisticated version, still using a single strip format, comprises a "Record and Read" head so that the user may record his or her own data. A further expansion of the system allows for the ferrite coating to be traversed in a number of predetermined tracks reading and/or recording, if required, in both forward and backward directions. By suitable choice of track width and care in the construction of the machine, an amount of data corresponding to at least a similar area floppy disc may be recorded.A significant advantage is that the "sectoring" of the card is virtually automatic, i.e. if more than one track is required to log the data, the recording head steps on one pitch and records and/or plays back on the next adjacent track. This is simple with a card since the beginning and ends of each track are defined by the ends of the card, the length of coating and/or the length of stroke of a traversing recording head. In the case of discs, when the recording head moves to an adjacent track which is carrying data related to the preceding one, it is essential to have some device to ensure that the pick-up point of the information fed to the computer is in the correct sequence. This is ususlly done by means of infrared photosensitive systems and, despite high basic speeds results in delay of the transmission of data either from, or to, the computer.Also the engineering required to ensure that the data recording or retrieval is accurate is of a very high standard.

Features and advantages of the present invention will become apparent from the following description of embodiments thereof when taken in conjunction with the accompanying drawings, in which Figures 1A and 18 show plan and side views respectively of a basic form of the invention; Figure 2 shows a perspective view of a further embodiment of the present invention; Figure 3 shows a plan view partly broken away to show the mechanical arrangement of the embodimenu shown in Figure 2; Figure 4 shows a sectional front view of the embodiment shown in Figure 2; and Figure 5 shows a diagram for explaining, in more detail the operation of the head moving mechanism shown in Figure 3; and Figure 6 shows a block diagram of a further embodiment of the present invention.

It has been found that, for example, a considerable number of games can be set up for playing with conventional tape recording systems running at 1.875" per second require between 5 to 20 secs. only to either record the data or feed it back into the computer. It is therefore convenient to consider a card approximately 6" in length carrying a single strip of ferrite 1/4" wide. Experiments have shown that the data can be recorded or retrieved very accurately by adopting a traverse speed of 0.938" per second, i.e. half the conventional tape speed, thus a 6" strip length can be used to record or play back information to set up a large number of simpler computer games and it is in this market where the use of the invention may be best channelled, since in order to purchase a game, a customer only has to pay for a card 6" x 4" with a pre-recorded strip.This, in real costs, is cheaper than conventional games recorded on a cassette by a factor of 10, and a factor of about 30 for solid state ROM cassettes. Read only equipment is cheaper than conventional tape recorder/players and does not allow the customer to 'pirate' copies and, indeed there will be less tempta tionforthemto do so if the games are available at a relatively low cost.

Read only machine A simple read only machine is shown in Figures 1A and 1 B to be a simple box-like structure 10 carrying a slot 11 into which the card 12 may be fed, pushing the card into the slot activates a switch 14 which turns on a motor 15 driving a pinch roller 16 which serves the additional purpose of traversing the card across the reading head. It is well-known that the linear speed constraints on binary data recording are less than required for audio work. In other words, a greater degree of "wow" and "flutter" can be accommodated. Thus, the traversing mechanism does not have to be as expensive as that used for audio work.

Simple readlwrite machine This machine will be similarto the Read Only type, but with the facility for recording using a common record/playback combination head such as that manufactured by Ikejiri Electric Co. Ltd. Upstream of the head is situated either a permanent magnet or AC erase head which is automatically brought into contact with the ferrite in the recording mode. It has been found that it is simple to use a multi-track read/write head to traverse a section of ferrite about 12mm. wide than to arrange for a single track head to be moved to operate on successive tracks; for example, an eight track head may be used with the tracks switched electrically to record on alternate paths of the card through the machine.Thus, for a long programme with a card 6" effective length, it is possible to obtain 48" of effective recording length which, at approximately 1" per second is 48 secs. of programme. This has been found to be more than adequate for complicated programmes which are used in the present Tv-type games with computers.

Aversion of the invention is described below, and is shown in Figures 2 to 4 of the accompanying drawings. A convenient format for the card 20 is 6" x 4" which is easily "mailable" and yet can contain sufficient ferrite coating area to be the equivalent of a 31/2" dia. floppy disc, in other words it can store about 200 kilobytes of information. The machine comprises a box 21 into which is built a frame to hold the card 20 in a static position, preferably against a glass or clear plastic support. The box 21 contains; 1. Recording/playback head 22 with a preferred recording domain width of 0.04(1 mm) 2. Erase heads 23, 24 which can be selectively electrically activated 3. An electronic circuit board 25 designed to match the input and output of the average home computer, and means for providing and recording MFM signals of suitable peak to peak voltage.

4. A motor-driven frame 25 carrying the playback/ record and erase heads which are conveniently drawn backwards and forwards across the surface of the card in the 'x' axis using a conventional oscillatory conveyor drive linkage which is shown diagram matically in FigureS. In Figure 5, the head or heads are mounted on a slide 26 provided with projections 26a and 26b. The slide 26 is driven to and fro at a constant speed by means of a projection 27 and a conveyor belt 27a which engages the projection 26a for movement of the slide in one direction and the projection 26b for movement in the opposite direction.

5. A means of automatically indexing the position of the head relative to the card in they' axis in either direction mode at the end of each traverse. In the drawings, the indexing in the 'y' axis is achieved mechanically using a lead screw 28 driven by a stepper motor 29 controlled by the computer to which the device is attached. The frame 25 then slides on parallel rails 30 under the control of the lead screw 28 and motor 29. Alternatively, or additionally, where a multi-track head is used 'y' indexing can be achieved electronically.

6. A means such as a microswitch for inhibiting the signal reception transmission at the end of each stroke, also in conjuction with (9) below 7. A manually adjustable arrangement for positioning the head of any pre-selected track. This may be conveniently operated by a cam device with a corresponding scale so that, if required, particular tracks may be selected at will 8. A means of inhibiting the stepping motion in the 'y' axis to ensure single line reading 9. A means corresponding with selected "cutouts", either physical or electronic, of card of inhibitng the erase feature of pre-selected lines. This will give the facility of formatting and permanent indexing.Since the head always traverses the full length of the active surface of the card and automatically steps up (a pre-set number of steps can be selected) at the end to the commencement of the adjacent line, the complicated arrangement for sectoring and consequent delay in data retrieval as used on the disc system is not needed, and the error rate is likely to be reduced 10. A means of adjusting the signal levels to match the input/output requirements of the computer with which the device is to be used 11. A means of providing power to the electric driven motor for the traversing mechanism, the pre-amplifier and erase circuits.These may be conveniently rechargeable batteries or provision may be made for direct-mains operation, although the power requirements of the device are small so that conventional dry batteries may be used obviating the risk of mains borne intereference causing incorrect information to be recorded or transmitted back to the computer.

From the above description it may be seen that the apparatus is considerably simpler than a floppy or standard disc drive and therefore can be manufactured much more cheaply and is suitable for home use. Because of the system of cards, the user can conveniently store data using conventional filing methods.

Retrieval time is fast and the "Record" facility allows the user to build up his own programmes from his own or other computers. Again, the cost of the cards compared with even un-protected floppy discs is extremely low.

Using traversing speeds of 0.938" per second (say 1" per second for convenience) it may be seen that with a 6" effective traverse length and 25 stripes per inch, a ferrite area 6" x 4" equals 960" of traverse distance or, at 1" per second, this is equal to 16 minutes of recording time. Thus, the data storage capacity is well in excess of the average home computer or small business computer requirement.

The front surface of the card may be conveiently used for manual index referencing or recording index track numbers so that it is not necessary to traverse the whole are of the card to find a particular line of information. Because the ferrite may be mounted on a card made of material chosen for its dimensional stability, the problem associated with floppy discs in storage is obviated since the ferrite may be printed or roller-coated on the card and no shrinkage or deformation due to "plastic memory" is experienced. (Unequal shrinkage is 'x' and 'y' axis caused track path to become oval with consequent problems of head following in disc formats.) The form of the apparatus can also allow for particular tracks or segments of data to be searched for electronically in the same way as with tape or floppy disc, if so desired.

The devices described above are intended to be connected to a computer via the "tape" port on the computer. However, with a card having sectored information it may be necessary to use the "disc drive" port.

Turning now to Figure 6 this is a block diagram of an improvement on the basic multi-track head arrangements disclosed above either for a Read Only Machine or for a ReadNVrite Machine. It is proposed to include buffer storage and to simultaneously energise all the transducers in the multitrack head and feed their outputs in parallel to the buffer storage device which can then be read out section by section to produce serial data.

The advantage of this arrangement is that the amount of data stored on a single strip of recording material can be maximised but only a single pass is required i.e. relative movement between the head and the recording material is only required once in order to replay all the material on the multiple tracks of the recording material. Further, because buffer storage is usually required for peripheral devices in any event so as to equalise data rates, it is not necessary to double the amount of buffer storage.

A simple read only machine is shown diagrammatically in Figure 1. A card 1 is provided with a strip 2 of a magnetic recording material. The strip 2 contains a plurality of tracks, the number depending on the width of the strip, the width of each track and the width of the guard bands between each track as well as the amount of data to be stored.

A multi-track head 4 is provided and relative movement is produced between the card 1 and the head 4 for example by moving the card 1 past the head 4 whereby to reproduce digital signals on all of the tracks simultaneously. The outputs from the mulit-track head 4 are fed in parallel over a data bus 5, the oblique stroke on which represents a number of data highways equal in number to the number of transducers in the multi-track head and the bus 5 is connected to inputs to a buffer store 6.

Once the card 1 has made a single pass past the head 4 and all the data contained on the tracks of the strip 2 has been stored in the store 6, the data can be put into serial form and fed at an appropriate rate to the computer. The reordering and data rate are controlled by two address generators. If one considers the store 6 to be made up of a number of rows of storage locations and one also assumes that.each row is capable of storing all the data on one track of the recording medium strip 2, then a first address generator 7 is used to connect each row of the store 6 in turn and for a predetermined time to an output 8 to the computer. During the time that row address generator 7 is connecting a particular row of the store 6 to the output 8, a further address generator 9 is reading out the data stored in that row so that the data is fed to the output 8.By adjusting the rate of operation of the further address generator 9 and the row address generator 7, the data read by the multi-track head 4 can be fed to the computer in serial form at a rate appropriate to the computer.

As stated above, this arrangement has two advantages namely that with a single pass a number of tracks containing data can be read simultaneously and also the data can be fed to the computer at the appropriate rate.

Various modifications may be made. For example a read/write variation can be produced so that data can be recorded on a plurality of tracks in simultaneously using the reverse of the technique described above. Further, more than one strip 2 may be provided.

Additionaily, the addressing of the store 6 can be altered as appropriate depending on the type of store used.

It is proposed in the above embodiments to use a record medium in the form of one or more strips of magnetic material on a non-magnetic carrier such as a card. It is possible for the carrier to be provided with one or more strips of magnetic material on opposite sides of the card with data recorded and/or replayed by means of one or more heads on either side of the card. In this way, in a single pass, the amount of data transferred can be at least doubled. It is necessary however to provide buffer storage.

Each head may be a single or a multi-track head and each strip may contain one or more tracks. If necessary, and if there are a plurality of strips on one side of the carrier, head indexing means as described above may be provided.

It is not necessary for the heads on either side of the carrier to be in register with each other but this may be a convenient way to put the modification into practice. Similarly, the strip or strips on one side of the carrir may or may not be in register with the strip or strips on the other side of the carrier.

Claims (5)

1. A data storage arrangement comprising a planar carrier member a portion of which is provided with a recording medium, a device provided with a transducing head and means for causing relative linear movement between the head and the recording medium whereby to cause data to be read from or written on the recording medium, the recording medium being provided with a plurality of data tracks.

2. An arrangement according to claim 1,wherein the recording medium is in the form of a strip of magnetic material containing a plurality of data tracks, the transducing head is in the form of a multi-track head and a storage device is connected to the transducing head.

3. An arrangement according to claim 1, wherein the recording medium is in the form of a plurality of strips of magnetic material each containing at least one data track and the device further includes means for indexing the transducing head in a direction transverse to the direction of relative linear movement between the head and the recording medium.

4. An arrangement according to claim 1,2 or 3, wherein the carrier is provided with at least one strip of magnetic material on each major surface and the device comprises a plurality of transducing heads, one for engagement with the strip or strips on one major surface and one for engagement with the strip or strips of the other major surface.

5. A data storage arrangement substantially as hereinbefore described with reference to the accompanying drawings.