JPS62242223A - Control system for external storage device - Google Patents

Abstract

PURPOSE:To shorten lapse of time until starting of a system by providing a decision means that decides propriety of access of the first external storage device and a control means that selects and accesses the second external storage device based on decision of the decision means. CONSTITUTION:Before a hard disk 8 becomes ready, output of an AND circuit 9 is low, and output of an AND circuit 10 is high. In the case where it is decided by a comparator 3 that the access is to a track registered in a table on a back-up memory 1, access is made to a floppy disk 7 through a floppy control circuit 5. As time after power source for the floppy disk 7 is made on until it becomes ready is several seconds, quick starting process becomes possible. When a hard disk 8 becomes ready, output of the AND circuit 9 is made high by a ready signal 4 and output of the AND circuit 10 is made low by an inversion circuit 11, and changed to proper access of the hard disk 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for an external storage device in a system using the external storage device.

[Prior Art] Demand for small hard disks used in personal computers and the like has increased in recent years due to their access speed and storage capacity. However, due to its structure, conventional hard disk drives have the disadvantage that it takes several tens of seconds from startup (power-on) until the device becomes accessible. This may not be a problem when used with a normal personal computer or word processor, but when used as a communication terminal with a remote power on/off device, it may take several tens of seconds to access the communication terminal. This is not preferable in terms of cost. In addition, it was impossible to drive the device with the power on all the time due to its durability. This applies not only to systems that simply use hard disks, but also to systems that use other external storage devices that are slow to start up.

[Problems to be Solved by the Invention] The present invention provides an external storage device control method that shortens the elapsed time until system startup, which is a drawback of the conventional example, and further allows different external storage devices to be used together.

[Means for Solving the Problem] As a means for solving this problem, the external storage device control method of the present invention includes a determining means for determining whether or not the first external storage device can be accessed; and control means for selecting and accessing the second external storage device based on the determination by the determination means.

Further, a determining means for determining whether or not the first external storage device can be accessed, and an address that designates a storage area of the first external storage device and an address that designates a storage area of the second external storage device are associated with each other. control for selecting and accessing the first external storage device and the second external storage device based on the storage means for storing the stored data and the determination by the determination means and the relationship between the addresses stored in the storage means; and means.

[Operations] In such a configuration, if the first external storage device is inaccessible, the second external storage device is used to start up and process the system, and when the first external storage device becomes accessible, Processing is switched to the external storage device of S2.

Furthermore, when switching processes, different external storage devices are used together.

[Example code] Examples of the present invention will be shown and explained below.

FIG. 1 is a diagram showing the configuration of a system according to a first embodiment. 1 is power backup memory (hereinafter referred to as backup memory)
The track address where the program was written to the floppy disk is written when the power is turned off. 2 is an address line from CPtJ. Reference numeral 3 denotes a comparison circuit which is activated by a ready signal 4 from the hard disk control circuit 6 indicating that the hard disk 8 is not ready, and switches between the hard disk 8 and the floppy disk 7 using an AND circuit 9 and 10 and an inversion circuit 11. . Reference numerals 5 and 6 indicate control circuits that control each of the hard disks 8 of the floppy disk. The system is CPU12 and R
It is controlled by AM13 and ROM14, and data is exchanged through data bus 15. When the system is powered on, it first tries to load the boot program stored in the ROM 14. However, in the conventional system, the hard disk 8 does not become ready until several tens of seconds have elapsed, so it takes several tens of seconds to start the system. On the other hand, in the startup method of this embodiment, the output of the AND circuit 9 is Low until the hard disk 8 becomes ready.
, the output of the AND circuit 10 becomes High, and if the comparison circuit 3 determines that the access is to a track registered in the table 8 on the backup memory 1, the floppy disk is output through the floppy control circuit 5. 7 is accessed. Normally, the access speed of the floppy disk 7 is much slower than that of the hard disk 8, but since it takes several seconds for the floppy disk to become ready after the power is turned on, the startup process is faster than waiting for the hard disk 8 to become ready. It becomes possible. When the hard disk 8 becomes ready, the output of the AND circuit 9 becomes High due to the ready signal 4, and the output of the AND circuit 10 becomes Low due to the % inversion circuit 11, so that the original hard disk 8
access.

Next, the processing procedure of the second embodiment in which the operations of the comparison circuit 3, AND circuit 9, 10, inversion circuit, etc. in FIG. Explain according to the following. The startup program is ROM14.
The data may be stored in the backup memory 1 or may be stored in the backup memory 1.

When the power is turned on, the CPU 12 reads the boot program and starts operation in step SIO. This boot program is programmed to read the basic processing program from the disk, and in step 320 requests access to the disk. When the reading of the basic processing program from the disk is completed, step S3
Execution of the basic processing program read by 0 is started, the system startup is finished, and the user's use is accepted.

Here, in this embodiment, the program processing shown in FIG. 2(b) is performed in response to the disk access request in step 320. In step S21, the hard disk 8 is accessed and checked to see if it is ready. If it is ready, the process goes to step S23 and the hard disk 8 is accessed.
Normally, when the power is turned on, the hard disk 8 is not ready, so the process goes from step S21 to step S22, and in step S22 it is checked whether the track to be accessed has been registered in the backup memory 1 in advance.
If it is registered, the floppy disk 7 is accessed in step S25. If not registered, step S2
4 to display an error.

When stopping the system, J, when it is determined to stop in step S40, the process goes to step S50, where the data necessary for starting the system is stored in the floppy disk 7, and in step S60, the data stored in the floppy disk 7 is stored in the backup memory 1. Remember the sector and shut down the system. Step S70 is a process of another system.

In this embodiment, the hard disk and floppy disk are controlled as independent devices, but if the floppy disk is incorporated into a single hard disk device, the load on the system can be reduced.

As described above, according to the structure of the system according to this embodiment, the hard disk can be booted and made usable by simply writing the system boot area etc. on the floppy disk in advance and storing the track information in the memory. Data can be read from the substitute floppy for several tens of seconds until the floppy disk is loaded, allowing the entire system to start up quickly. Furthermore, according to the first embodiment, since the disk is substituted by a part closer to the hardware without depending on the operating system, etc., when the hard disk becomes ready, access to the hard disk is switched to, and various Enables the fastest boot-up when the hardware is ready.

FIG. 3 is a system configuration diagram of the third embodiment. In this system, the floppy disk is used not only for system startup but also for processing, and after the hard disk has started up, it is smoothly switched to the hard disk. 31 is a hard disk, 32 is a hard disk control circuit, 33 is a control signal to the hard disk control circuit, and 34 is a hard disk ready signal. 35 is a floppy disk, 36 is a floppy disk control circuit, and 37 is a control signal thereof. 38 is a memory with battery backup (hereinafter referred to as backup memory), and 39 is a control section. 40 is a CPU 41 and a ROM 42. This is a data bus that connects the RAM 43 and the control unit 39. FIG. 4(a) shows an example of the structure of a table in the backup memory 38, and FIG.
b) shows an explanatory diagram of the table flags.

The operation will be explained according to the processing flowchart of the control section shown in FIGS. 5(a) and 5(b).

FIG. 5(a) shows the case of reading, and in step S51 the table in the backup memory 38 is searched to check whether a valid sector address is stored. If there is no valid sector address, the process goes to step S55 to read data from the hard disk 31 and end the process. If there is a valid sector address, it is checked in step S52 whether the flag indicates a write track of 3", that is, whether the floppy disk 35 has been updated. If it has been updated, the floppy disk 35 is checked in step S53. Read the data.

If the hard disk 31 has not been updated, it is checked in step S54 whether the hard disk 31 is ready, and if it is ready, the hard disk 31 is checked in step S55. If the hard disk 31 is not ready, data is read from the floppy disk in step S53. At this time, if the flag in the table is "1" indicating the boot track, it is data for the boot program and will be unnecessary after being read once, so go from step S56 to step S57 and set the flag to boot. From 1” indicating a track to “O” indicating a dummy track
” so that it can be used for other purposes.

FIG. 5(b) shows the case of writing, in which it is checked whether the hard disk 31 is ready in step S58, and if the hard disk 31 is ready, it is written to the eight-hard disk 31 in step S64, but at this time, it is registered in the table in step S63. If it is registered in the table, the flag is changed to "O" indicating dummy in step S65. This is because the data on the floppy disk 35 becomes unnecessary. hard disk 31
If it is not ready, the corresponding sector in the table is searched for in step S59, and if it is found, it is written there in step S60, and the flag is changed to "3" indicating a write track. If not found, the sector address of the hard disk 31 to be written is written in the entry whose flag is "0" indicating the dummy track in step S62, and the data is written in the entry in step S660-61, and the flag is set to "3" indicating the write track. change. In addition, the data of the flag location of the light track remaining in the table is
The data is copied to the relevant location on the hard disk 31 before the power is turned off.

In this example, the control section has been described as a device independent from cpυ, but the operation of the control section may be performed by the CPU.

In that case, FIG. 5(a).

The processing program shown in (b) will be stored in the ROM 42.

As described above, according to the system configuration of the third embodiment, programs including booting and disk input/output can be executed for several tens of seconds until the hard disk is started and becomes usable. , and processing can be executed without any interruption even when the hard disk becomes ready.

Furthermore, this embodiment is intended not only for system startup, but also for a control method for backing up the hard disk during normal operation and for using multiple disks (hard disk and floppy disk in this example) together.

In addition, although the hard disk and floppy disk in the first to third embodiments are referred to as external storage devices, this does not indicate their physical location, and may be included in the main control unit of the system. It may also be used as internal storage as system memory.

Further, the backup memory may also be included in the disk device, or in the main control unit, and may also be shared with the ROM and RAM.

[Effects of the Invention] As described above, according to the present invention, it is possible to shorten the elapsed time until system startup in a system using an external storage device, realize backup of the external storage device, and use different external storage devices together. It is possible to provide a control method for an external storage device.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of the system of the first embodiment, Figure 2 (a
), (b) are flowcharts of the startup program of the second embodiment, FIG. 3 is a system configuration diagram of the third embodiment, and FIG. 4(a)
, (b) are examples of the logical structure of a table in the backup memory, and FIGS. 5(a) and 5(b) are flowcharts showing the processing contents of this embodiment. In the figure, 1... Backup memory, 2... Address signal, 3... Comparison circuit, 4... Ready signal, 5...
... Floppy disk control circuit, 6... Hard disk control circuit, 7... Floppy disk, 8...
Hard disk, 9.10...AND circuit 11,...
・Inversion circuit, 12-CPU, 13-RAM, 14-RO
M, 15...Data bus, 31...Hard disk, 32...Hard disk control circuit, 33...Control signal, 34...Ready signal, 35...Floppy disk, 36...Floppy disk control circuit, 37
...Control signal, 38...Backup memory, 39
...Control unit, 40...Data bus, 41...CP
U, 42...ROM, 43...-RAM. Patent applicant Canon Corporation Figure 1 Figure 2 Figure 4 (b) Figure 5 ('CI)

Claims (6)

[Claims] (1) In a system using an external storage device, the first
A second external storage device is provided with a determining means for determining whether or not an external storage device can be accessed, and a control means for selecting and accessing a second external storage device based on the determination by the determining means, so that an inaccessible external storage device can be accessed. A control method for an external storage device characterized in that an external storage device is substituted for the external storage device. (2) The control method for an external storage device according to claim 1, wherein one of the external storage devices is a hard disk. (3) The control method for an external storage device according to claim 1, wherein one of the external storage devices is a floppy disk. (4) In a system using an external storage device, the first
determining means for determining whether or not the external storage device can be accessed; and storing an address indicating a storage area of the first external storage device and an address indicating a storage area of the second external storage device in association with each other. storage means; and control means for selecting and accessing the first external storage device and the second external storage device based on the determination of the determination means and the relationship between the addresses stored in the storage means; 1. A control method for an external storage device, comprising: substituting an inaccessible external storage device with an accessible external storage device; and further using different external storage devices together. (5) The control method for an external storage device according to claim 4, wherein one of the external storage devices is a hard disk. (6) The control method for an external storage device according to claim 4, wherein one of the external storage devices is a floppy disk.