JPS63240616A - Rom/ram disk device - Google Patents

Abstract

PURPOSE:To obtain a ROM/RAM display with which a specific file can be written and a fast access is possible by using the combination of a ROM of large capacity and a backed-up RAM of small capacity to a disk operating system DOS so that the advantages of both the ROM and the RAM are utilized. CONSTITUTION:Most of the area of a format using an MS-DOS of a ROM/RAM disk 20 is formed by a ROM and the greater part of the MS-DOS is included in said ROM area. While a specific partial area is formed a RAM using a writable file part. The ROM includes a reservation area 21, an FAT22, a direc tory 23a of the writable file part, other directories 23b, and the measurement data (programs) 24 and 25. Then a rewritable file 26 consists of a RAM. Further more a system includes an application software 11, a DOS12 where a software interruption is produced, a ROM-B10S13 serving as a firmware which performs an I/O process of a low level, and a hardware 14.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a ROM/RAM disk device for replacing a flexible disk device or a hard disk device with a static storage device such as a semiconductor storage device. In particular, R
The present invention relates to a ROM/RAM disk device that uses OM and RAM in combination and is inexpensive and can have files that can be written and accessed at high speed.

(Conventional Technique #4) When replacing a floppy disk or hard disk device with a semiconductor device, a means for replacing it with ROM (ROM disk mechanism) and a RAM1. : means to change ill (RA
M disks all) can be considered.

However, although the ROM disk mechanism is inexpensive in terms of cost, it is inconvenient that it cannot be written to and therefore cannot have a rewritable file section. Further, since the RAM disk mechanism is writable, it is possible to have a rewritable file section, but there is a problem in that it is expensive in terms of cost.

(Problems to be Solved by the Invention) As described above, conventionally there has been no highly practical and effective means for replacing a floppy disk or hard disk device with a semiconductor device.

The present invention has been made in view of the above points, and the ROM
The combination of large ROM and small backed-up RAM allows for fast access to R that allows specific files to be written to.
The purpose is to provide OM/RAM disks.

[Structure of the invention] (Means and effects for solving the problems) The present invention
A ROM/RAM disk in which RAM is used in some areas forming an OS (disk operating system) area and ROM is used in other areas, and means for determining whether or not the disk to be accessed is the ROM/RAM disk. and a means for converting a disk address into an address specific to the ROM/RA~1 disk when accessing the ROM/RAM disk, and is specified by a combination of a large capacity ROM and a small capacity backed up RAM. This configuration is a ROM/RAM disk am that can be accessed at high speed and allows files to be written to it.This makes it possible to use both ROM and RAM to have files that are inexpensive and can be accessed and written at high speed.

(Example) Hereinafter, the RO to 1/RAM disk of the present invention will be explained with reference to the drawings.

In explaining the present invention in detail, the technical background of the present invention will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a diagram showing a system configuration for explaining the present invention in detail. In the figure, 11 is application software, 12 is OOS that issues software interrupts,
For example, Microsoft's MS-OOS 13 is a ROM that is firmware that performs low-level I10 processing.
-BiO2,14 is hardware.

Figure 5 shows the M S-D O on the floppy disk.
15 is a reserved area, and 16 is a diagram showing the format of S12, where 15 is a reserved area and 16 is a FAT (File A
1location Table) and 18 is a data area.

FIG. 4 shows the application software 11, MS-
It shows how the DO 812, ROM-BIO 813, and hardware 14 operate when accessing a file.

Application software 11 is MS-D OS
When you issue a file input/output request to MS-D
The O812 sends a software interrupt to the ROM-810813, for example, a software interrupt [lNT13
H] (in this example, a floppy disk I10 processing routine) is issued. This allows ROM-810S
13 actually reads/writes to/from the hardware 14.

FIG. 5 shows the format of MS-DO812 on a floppy disk. Each file has its own directory in the directory area 17. This directory contains information such as file size, name, and starting FAT.

When inputting/outputting a file, select [File name → Directory →
The sector to be actually accessed is determined in the following order: FAT→actual sector on the disk].

Here, in order to access the sector on the actual disk, the MS-DO 812 issues the above-mentioned software interrupt [lNT13H1 to the ROM-BIO 813.

Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows the MS-OOS format of the ROM/RAM disk 20 according to the present invention, where most of the area of the ROM/RAM disk 20 is RO.
Most of the MS-OOS is included in this, and only a specific part of the area (only the writable file part) is made up of RAM. That is, here, a reserved area 21, a FAT 22, a writable file section directory 23a1, other directories 23b, and a fixed data (program) storage area 24.2.
5 and the like are each configured with a ROM, and only the writable file section 26 is configured with a RAM. Here, the file name of this writable file section 26 is [config].
o-sys ].

Access to this [config-sys] 26 is similar to the access procedure described above.
sys 26 → directory 23a −+ F A
The sector to be accessed is determined in the order of T22→Seceftaco on the actual disk, and the software interrupt [lN
T13. ] is issued.

Here, the software interrupt [lNT13. ] Describes the external specifications.

Interrupt [lNT13. ] is a software interrupt for Intel's 16-bit microprocessor 8o86 series, as described above, and the register of the processor 8086 has the following information:
By setting a certain value and executing the command [lNT13H], this example becomes one routine of ROM-BiO2 that processes disk I10.

Table 1 shows a specific example of the correspondence between the value of the register (AH register) and the command at this time, and various commands shown in Table 1 are executed depending on the value of the AH register.

Here, the cases of AH=158 and AH=03+ will be explained in particular.

1, AH = 15H (lead drive type) crab AH
-15+ OL"'00M, 01H (drive 0.1) Out crab D
L=ooH<no drive): DL-018 (floppy disk): DL-02+
(Hard disk): DL-03+ (ROM/
(RAM disk) When the input is given as described above, the drive type of the system drive O11 can be determined from the value of the output DL register.

2, AH=03H (write sector) Input A H=03H AL-Number of write sectors, DL=Drive number, DH-Head number CH=Cylinder number CL=Sector number ES:BX=Memory address of X-write buffer When input is given as shown above at the beginning of , the contents of the buffer specified by ES:BX are written to the drive by A L x 512 bytes (capacity ω of one sector).

Next, the format of the ROM/RAM disk 20 will be described.

A specific example of addressing the ROM/RAM disk 20 is shown in FIG.

As shown in FIG. 2, the ROM/RAM disk 20 can be addressed in the order of sector, head, and track of the floppy disk. Therefore, the format of the MS-DO8 is as shown in FIG. 1, similar to a floppy disk. Also, some data areas in this area have a RAM configuration, and in this example, the [config ig-sys directory
a → FAT22 → RAM (I can be included) 2
6] exists at the specified address.

To support such ROM,/RAM disk 20, software interrupt [lNT13H]
distinguishes between the ROM/RAM disk 20 and the floppy disk/hard disk according to the specified drive number and performs various operations. FIG. 5 shows the processing flow of the disk input/output processing firmware that supports the ROM/RAM disk 20 at this time.

Here, the operation of the software interrupt [lNT13H] issued when accessing [coMig-sys] will be considered.

Here, AH-3, AL-1, DH-0°DL-1,
Assume that it is CH-10, 0L-2 (write operation to head 0, track 10, sector 2 of drive #1) (that is, the contents of config.sys are contained in this sector).

INT 13. When the process starts, it is first determined whether the disk is a ROM/RAM disk according to the specified drive number (step Kl in FIG. 5).

Here drive #1 is ROM/RAM disk 2
If it is not 0 and is a floppy, write is actually performed to this sector (step 2 in FIG. 5).

Also, if drive #1 is a ROM/RAM disk 20, the ROM/RAM disk is determined from the track, head, and sector number.
Find the address for disk access (step 3 in Figure 5), and if the address is in the RAM area,
Data is written to the same RAM (ie, writable file section 26). Furthermore, if the above address is in the ROM area, writing is not possible, so an error is returned (step 3 in FIG. 5).

The operation of writing to this RAM (writable file 81126) is realized by the present invention described above.

By using the ROM/RAM disk device of the above-described embodiment, a highly practical, inexpensive, and high-speed O8 can be easily realized. In other words, DO8 is a ROM/RAM disk that has writable files that conventionally could not be held on a ROM disk, and that can be written at high speed at low cost by using a combination of a large-capacity, inexpensive ROM and a small-capacity, backup-capable RAM. can be easily realized.

Although the above-mentioned actual flow example has been described using the MS-DO8 as an example, the present invention is not limited to this, and can be applied to any O8 that manages disks in the format shown in FIG.

Further, the ROM used in the ROM/RAM disk 20 may be another read-only device, and the RAM may also be a storage device that can be programmed and data can be backed up.

Also, ROM-8108 software interrupt [lN71
3H] is unique to IBM personal computer compatible machines, and includes floppy/hard disk and ROM/RA.
Any disk I10 routine that can handle M disks with an external interface may be used.

Furthermore, although the above embodiment has been described in accordance with the MS-DOS format, it is not limited to MS-DOS, and any O8 that has a directory for managing files may be used.

[Effects of the Invention] As detailed above, according to the present invention, a ROM/RAM disk in which RAM is used in some areas forming the DO8 area and ROM is used in other areas, and R
means for converting the disk address into an address specific to the ROM/RAM disk when accessing the AM disk, so that a particular file can be occupied by a combination of a large capacity RO~1 and a small capacity backed up RAM. By configuring a ROM/RAM disk device that can be loaded, it is possible to have files that are inexpensive, can be loaded, and can be accessed at high speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the format of a ROM/RAM disk in one embodiment of the present invention, and FIG. 2 is a diagram showing the format of the ROM/RAM disk in an embodiment of the present invention.
FIG. 3 is a flowchart showing the processing flow of the disk input/output processing firmware that supports the ROM/RAM disk; FIG. 4 is a system configuration diagram for explaining the present invention in detail. FIG. 5 is a diagram showing the MS-DOS format on the floppy disk. 20...ROM/RAM disk, 21...Reservation (
Reserved) area, 22...FAT, 23a...Writable file section directory, 23b...23
Directories excluding a, 24. 25... Fixed data (program) storage area, 26... Writable file section (file name: config -S yS
). Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] RO uses RAM in some areas forming the disk operating system area and ROM in other areas.
The M/RAM disk and the disk to be accessed are the above R.
means for determining whether or not the disk is an OM/RAM disk;
A ROM/RAM disk device comprising means for converting a disk address into an address unique to the ROM/RAM disk when accessing the ROM/RAM disk.