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- COMBI-Disk -
- RAM disk & disk cache
-
-
- Preface.
- --------
-
- - Why don't You use disk cache?
- - I'd like, but memory constrains prevent me from using it:
- I need more memory for RAM disk.
- -----
- - Why don't You use RAM disk?
- - I'd like, but memory constrains prevent me from using it:
- I need more memory for disk cache.
-
- If one of these answers is Yours then COMBI-Disk is for You!
- You may hit two targets with a single shot - installing COMBI-Disk You
- get a RAM disk and a Disk-Cache at the same time in the SAME area of
- extended memory!
-
- When You install COMBI-Disk You specify amount of extended memory for it
- and You get a RAM disk of the specified size and a Disk-Cache of the
- same size. Then when You work with Your PC, You enjoy Disk-Cache which
- is not better but not worse than others. Suppose now that You start a
- program which needs a disk buffer for temporary storage and tell it to
- use RAM disk. Then the program may use the whole amount of the RAM disk's
- space (though contracting the size of cache). When it terminates and
- deletes temporary files You get back your cache buffer!
-
-
- Applications.
- ------------
-
- Some programs (e.g. compilers, word-processors etc.) need a buffer for
- temporary storage, and if the storage is RAM disk then their performance
- may be increased few times compared with the case of usage of hard disk
- instead. That's why You may sometimes need a RAM disk. But if You use
- standard RAM disk (Microsoft (C) RAMDRIVE.SYS or IBM (C) VDISK.SYS or any
- other) it often comes out that it stays empty most of the time though
- consuming Your extended (expanded) memory. That's why You may wish to
- give up using RAM disk or make it less in order to have more memory
- for Disk-Cache which is always useful.
-
- Don't get disappointed!
- COMBI-Disk
- is a great solution of this problem! It uses a bit more memory for RAM disk
- than is needed to keep all files written into it while all the remaining
- memory is used for cache. You need not bother to make this memory larger -
- just WRITE Your file(s) into RAM disk, all the rest it does itself! You
- need not bother as well to contract RAM disk's size and increase cache
- size - just DELETE files from RAM disk and all the released memory will be
- used for cache!
-
-
- Installation.
- ------------
-
- COMBI-Disk installation process is quite straightforward, although it
- requires some tweaking with the contents of your CONFIG.SYS file.
- Copy COMBI.SYS into Your hard-disk and place the following line into Your
- CONFIG.SYS file
-
- DEVICE=[drive:][path]COMBI.SYS [size] [/V [sectsize [rootsize]]]
-
- where the parameters mean:
-
- "size" - the amount of extended memory (Kbytes) You want
- to use for COMBI-Disk. Minimum is 128K, maximum is
- 32000K. If it is omitted then all available memory
- is default.
-
- "sectsize" - sector size of You RAM disk - 128, 256, 512 bytes
- allowed, default is 512 bytes.
-
- "rootsize" - number of files You want RAM disk to be capable
- to keep in ROOT directory (default is 64). This
- number may be adjusted by COMBI-Disk depending on
- sector size.
-
-
- System requirements.
- -------------------
-
- 1. 80x86 based machine with extended memory.
- 2. DOS 3.30+.
- 3. Extended memory manager which supports XMS 2.0 specifications
- (Microsoft (C) HIMEM.SYS or Quarterdeck (C) QEMM.SYS will do).
-
-
- Installation messages.
- ---------------------
-
- COMBI-Disk: Incorrect DOS version
-
- - COMBI-Disk may work only under DOS 3.3 or higher.
- COMBI-Disk is not installed.
-
- COMBI-Disk: Extended Memory Manager not present
-
- - COMBI-Disk needs XMM driver. Check that Your XMM driver
- is installed before COMBI-Disk.
- COMBI-Disk is not installed.
-
- COMBI-Disk: Invalid parameter
-
- - You have specified invalid parameter in command line.
- Check Your CONFIG.SYS file.
- COMBI-Disk is not installed.
-
- COMBI-Disk: No hard drives on system
-
- - COMBI-Disk's cache works only with hard-disks, so if
- You have no hard-disks installed there is no reason in
- using COMBI-Disk.
- COMBI-Disk is not installed.
-
- COMBI-Disk: No extended memory available
-
- - All Your extended memory is used by some other programs
- or less than 128K is available.
- COMBI-Disk is not installed.
-
- COMBI-Disk: Error in extended memory allocation
-
- - An error encountered when COMBI-Disk tried to allocate
- extended memory.
- COMBI-Disk is not installed.
-
- COMBI-Disk: RAM disk & disk cache
- Copyright (C) by Vadim V. Vlasov, Moscow, 1991.
- Version 0.20
-
- - COMBI-Disk is installed and its parameters are following.
-
- Creating virtual drive ?: - ? stands for drive letter of Your
- RAM disk.
- Total size: xxxxK in Extended Memory
- - the size of RAM disk.
-
- Number of root directory entries: xxx
- - maximum number of files in root
- directory.
-
- Cluster size: xxx sectors - number of sectors in allocation unit.
-
- Sector size : xxx bytes - sector size.
- Cache: room for xxx tracks of xxx sectors each
- - size of disk-cache.
-
-
- Possible errors.
- ---------------
-
- Sector not found - You tried to read a sector which does not
- contain any valid data (You haven't written into it yet or have already
- deleted the file that occupied this sector).
-
- Warning! Once a file is deleted from RAM disk, it might not be correctly
- unerased by any means. It's data is lost immediately.
-
- Other errors indicate that either COMBI-Disk internal data tables
- are corrupt (e.g. overwritten by other program) or error in XMM driver
- encountered.
-
-
- General information.
- -------------------
-
- Version 0.30 (08 Nov 1991):
-
- Performance of delete from RAM disk operations increased compared to
- previous versions.
-
- For certain configuration parameters (e.g. 320 /v 128 256) COMBI-Disk
- created FAT larger than really needed. However, it was O'K for DOS 5.0
- but led to errors with DOS 3.30.
- - Now it is fixed.
-
- Version 0.20 (28 Oct 1991):
-
- A bug has been discovered in version 0.10: RAM disk failed after an
- attempt to write into boot sector and one or more sectors of FAT.
- - Now it is fixed.
-
- DOS 4.0+ CHKDSK did not work with version 0.10 due to simplified
- format of boot sector of RAM disk.
- - This is now corrected for MS-DOS 5.0 but some DOS versions need
- a certain text be written into boot sector (e.g. for IBM-DOS 4.0
- it is "RDV 1.20" at offset 3 of boot sector). If You are aware
- what You are doing, You may correct this problem for Your DOS.
-
- Version 0.10 (13 Aug 1991):
-
- The very first beta version of COMBI-Disk was version 0.01 (24 Jun 1991).
- In this version (0.10) two minor bugs have been fixed:
- A. COMBI-Disk v.0.01 refused to work under DOS 3.30 - not
- just it couldn't but only refused.
- B. Device return codes were corrected.
- No any serious bugs were discovered yet.
-
-
- ----------------
- If You have any questions, comments or find out any problems with its
- usage please contact:
-
- Vadim V. Vlasov,
- Inst. for Nuclear Research of the USSR Acad. Sci.,
- 60th October Anniversary prospect, 7a,
- 117312, Moscow, USSR
-
- phone: 7-095-133-6533
-
- Internet: vvlasov@inucres.msk.su
-
-
- Future versions will include:
- EMS support,
- maybe faster performance,
- other features depending on Your suggestions.
-
- License.
- -------
-
- Copyright (C) 1991 by Vadim V. Vlasov, All Rights Reserved.
-
- You are free to use, copy and distribute COMBI-Disk for
- noncommercial use if:
-
- no fee is charged for use, copying or distribution.
-
- it is distributed together with this README file
-
- it is not modified in any way.
-
- Note:
- This program is provided AS IS without any warranty, expressed or
- implied, including but not limited to fitness for a particular
- purpose.
-