rld@druri.UUCP (DucharmeRL) (04/21/86)
I have a AT&T PC 6300+ (20 MB Disk) with MS-DOS 3.1. When I run the format command I get cluster sizes of 8K. I tried the following method to modify the BPB: fdisk format c: debug l 0 2 0 1 e 0d put in the 4 instead of the 10 e 16 put in the 15 instead of the 08 w 0 2 0 1 q format c:/s The sets the number of sectors per allocation to 4 (2K) and the FAT size to 21 sectors (don't ask me why). However, when the second format is done to make it a system disk, the BPB is overwritten with the old data. I tried several kludges to correct this and not have to do the final format but was unsuccessful. This method is the method in the APRIL PC-WORLD. Please respond however you can. The following is my UNIX mail address and phone number. Thanks. Robert Ducharme ihnp4!druri!rld (303) 538-4066
reintom@rocky2.UUCP (Tom Reingold) (04/29/86)
There has been a lot of discussion on hard disk sector size
modification. Most of it has been for the AT&T machines. Is there
a tried-and-true method for doing it on an IBM machine? Would the
method be the same? I am using an IBM XT with the stock 10 MB
disk. I replace the stock controller board when it gave out. I
now use a Datatech board.
Would the method be specific to the machine, DOS, disk, or
controller board?
I found no option to do this in the XT's Advanced Diagnostics disk.
Tom Reingold
Rockefeller University
New York City
{seismo|ihnp4}!cmcl2!rna!rocky2!reintomreintom@rocky2.UUCP (Tom Reingold) (04/29/86)
Oops. In my previous article I used the word "sector" when I meant
"cluster".
Please don't assume that I am stupid just because I chose the wrong
word. Some people make that assumption, you know. You may even
have seen it!
Tom Reingold
Rockefeller University
New York City
{seismo|ihnp4}!cmcl2!rna!rocky2!reintombrown@nicmad.UUCP (04/30/86)
In article <182@rocky2.UUCP> reintom@rocky2.UUCP (Tom Reingold) writes: > > >There has been a lot of discussion on hard disk sector size >modification. Most of it has been for the AT&T machines. Is there >a tried-and-true method for doing it on an IBM machine? Would the >method be the same? I am using an IBM XT with the stock 10 MB >disk. I replace the stock controller board when it gave out. I >now use a Datatech board. > >Would the method be specific to the machine, DOS, disk, or >controller board? The following patches are specific to PC-DOS 3.10. The patch to make 10MB hard disk 4K clusters into 2K clusters will only work on PC-DOS 3.10 or 3.20. I have have used the cluster mod on 3.10 and am now using it on 3.20. (See a previous posting about a problem in converting from 3.10 to 3.20) So, for you and those of you who have missed the patches, here they are again. The CompuServe IBMPC SIG Users Group ------------------------------------ PATCHES FOR IBM DOS 3.1 ----------------------- ************************************************************************ Note: In the patches which follow, it is assumed the user is familiar with the use of DEBUG. The notation "xxxx" means "anything is ok". The notation <cr> means press Enter. ************************************************************************ FIXED DISK CLUSTER SIZE If you have a 10 Meg hard disk, the following information collated by Bill Higgins, provides for 2K clusters instead of the standard 4K clusters. Typically, you will free up about 10% of the disk space you are currently using. 2K Cluster Size for 10MB Fixed Disks under DOS 3.1 Standard 10mb fixed disks formatted under DOS 3.1 utilize 4k clusters (i.e., the minimum space allocated to any file is 4096 bytes), while drives 20mb and larger utilize 2k clusters. I use a PC with twin 10mb drives under DOS 3.1. Since I have a multitude of small files on these disks, the smaller allocation unit's space saving advantage far outweighs any theoretical disadvantage of additional overhead for DOS to handle the added allocation units. With the help of Bob Morse, SysOps Jim Gainsley, and Conrad Kageyama, and the DOS Technical Reference, I was able to make the changes necessary to use 2k clusters on both of my 10mb drives. By following the step-by-step instructions below, you will be able to make the switch to 2k clusters yourself. NOTE: THE FOLLOWING PROCEDURE WILL DESTROY ALL DATA ON THE FIXED DISK!!! You will need the following: (1) IBM PC-DOS version 3.1 (3.0 appears NOT to work). (2) A disk utility such as DISK REPAIR (a part of the IBM PROFESSIONAL DEBUG FACILITY), or DISMOD (a USS program, available on many BBS's), or equivalent. Note: You will not need this, if you use the Alternate Method in #4a below. Most critical to the process is the sequence in which this procedure is attempted. Here is the 4k to 2k cluster procedure: (1) Do a complete backup of the fixed disk, using your current version of DOS. (2) Cold boot DOS 3.1, run FDISK to create or be sure that a DOS partition exists on the Fixed Disk. (3) Format the fixed disk using the DOS 3.1 FORMAT.COM program. Do NOT use any parameters (no /s or /v). (4) Using your disk utility, select the boot sector and view it. See below for an explanation of the pertinent info in this sector. At location AA below, you should see a value of 08 which is the number of sectors per cluster. Change this to 04. At location BB below, you should see a value of 0800 which is the number of sectors per fat (in hex Word format). Change this to 1500. The results should appear as in CC and DD below. All changes to the fat sectors required for 2k clusters will be accomplished by the subsequent format in instruction 6 below. No other manual changes are required. -------------------- Example of first few bytes in the Boot Sector of the fixed disk, displayed in hex format, after formatting with DOS 3.1, and prior to 2k cluster size changes: (The bytes of interest are located at Boot sector Offsets 0Dh = Sectors per cluster, and 16h = Sectors per FAT.) EB299049 424D2020 332E3100 02080100 020002F3 50F80800 ^^ ^^^^ AA BB After the 2k cluster size changes: EB299049 424D2020 332E3100 02040100 020002F3 50F81500 ^^ ^^^^ CC DD Where the data elements directly above AA are sectors per cluster, and above BB are sectors per FAT. (4a) Alternate Method: If you would rather, and if you are familiar with the operation of Debug, the following method can be used. Under DOS 3.1, do: DEBUG -L 0 n 0 1 <cr> -E 0D <cr> xxxx:0D 08.04 <cr> -E 16 <cr> xxxx:16 08.15 <cr> -W 0 n 0 1 <cr> -Q where, n = the fixed disk drive as follows: If fixed disk is drive B then n=1 " C " n=2 " D " n=3 " E " n=4 NOTE: Be *really* careful when you do the L and W commands in the foregoing sequence. Would be best to check your work by doing DEBUG, then -L 0 n 0 1 <cr> then doing -D 0D L1 <cr> and -D 16 L1 <cr> making sure that the results are 04 & 15 respectively. Then exit by doing -Q ------------------- A more detailed explanation of these two changes: The number of sectors per cluster would change from 08 to 04, since that's what this is all about. The sectors per FAT will change, in order to accomodate (1) the increased number of possible FAT entries, and (2) the increased size of each fat entry which will be in 16-bit format instead of the former 12-bits. The value to use for a 10 meg & 2k clusters would be 21 sectors, or 1500 in hex word format. (In this case the 15 is all that counts. 15 hex = 21 decimal.) (5) Exit the disk utility and do a cold boot with DOS 3.1. This is critical, since the boot sector is read by DOS only once, at boot time, in order to build the BIOS Parameter Block. Having different info in the boot sector than what's in the memory-resident BPB will give UNPREDICTABLE RESULTS. The following is safest way to preceed. Please use it. (6) Reformat the drive using the DOS 3.1 FORMAT.COM, FORMAT C: /S (You may also include /V, if you wish to include a volume label.) DOS 3.1 FORMAT will NOT affect your changes to the boot sector. (This a change from DOS 3.0 FORMAT, which re-writes the boot sector.) (7) Restore your files, BEING SURE TO USE the RESTORE parameter, /P which prompts before restoring system files. **** WARNING **** YOU MUST NOT ALLOW THE TWO SYSTEM FILES, IBMBIO.COM AND IBMDOS.COM TO BE RESTORED, EVEN IF THEY ARE DOS 3.1 !!! IF YOU DO, THEY WILL NOT BE PUT IN THE PROPER LOCATIONS AND YOUR FIXED DISK WILL NOT BE BOOTABLE AND YOU WILL HAVE TO REFORMAT !!! Avoid restoring an earlier version of COMMAND.COM, but if you do restore an earlier version, nothing is lost, just be sure to copy a 3.1 version over it afterwards. You should now be operational again, with 2k clusters. Further info on the entries in the boot sector entries used to build the BIOS Parameter Block can be found in the DOS 3.1 Technical Reference, Page 2-28. Of course, I cannot warrant that this change will work for all controller/disk combinations, particularly for controllers and drives which are not 'XT clones' though it 'should work' for all drives compatible enough to work under DOS 3.1. Comments to: -- Bill Higgins [70575,307] CIS, IBMPC SIG -- ********************************************************** ENVIRONMENT SIZE Thanks to Bob Morse, the environment size can be patched as follows: DEBUG COMMAND.COM -E 0D11<cr> xxxx:0D11 0A.1E<cr> -W<cr> -Q<cr> (1E is for a 544 byte nominal size. Use 3C for a 1K size.) ********************************************************* SCREEN SCROLLING From Ward Christensen, the ANSI.SYS scrolling patches to disable the wait for retrace and the screen blanking have new addresses but they work just fine. Using DEBUG, proceed as follows: DEBUG ANSI.SYS -E 02E3<cr> xxxx:02E3 74.90 FB.90<cr> -E 02EA<cr> xxxx:02EA EE.90<cr> -W<cr> -Q<cr> ********************************************************** DISABLE EDLIN AUTOMATIC .BAK FILE CREATION On a BBS I found the patch from an unknown author to disable the automatic .BAK file when using EDLIN. Using DEBUG proceed as follows: DEBUG EDLIN.COM -E 0CD5<cr> xxxx:0CD5 56.41<cr> -W<cr> -Q<cr> ********************************************************** AUTOMATIC INSTALLATION OF PRINTER FOR DOS PRINT Also on a BBS I found the patch by an unidentified author to PRINT.COM to obviate the need to type the desired printer port. If the printer port is LPT1, then using DEBUG proceed as follows: DEBUG PRINT.COM -E 1788<cr> xxxx:1788 E8.90 CB.90 02.90<cr> -E 179A<cr> xxxx:179A CD.90 21.90<cr> -W<cr> -Q<cr> If the printer port is LPT2 then the following address must ALSO be modified as follows: -E 10CA 4 "LPT2" ********************************************************* DISABLE AUTOMATIC HEADER IN FIND.EXE OUTPUT The FIND program puts an automatic header ---------- filename in the output listing. To disable this header, patch FIND.EXE as follows: REN FIND.EXE FIND.TMP DEBUG FIND.TMP -E 0424<cr> xxxx:0424 03.2C<cr> -W<cr> -Q<cr> REN FIND.TMP FIND.EXE ********************************************************** PERMIT MORE THEN 10 MISMATCHES IN COMP.COM I have patched COMP.COM to permit 50 mismatches as follows: DEBUG COMP.COM -E 08E2<cr> xxxx:08E2 0A.32<cr> -E 0BF8<cr> xxxx:0BF8 31.35<cr> -W<cr> -Q<cr> ********************************************************** ECHO OFF I have patched COMMAND.COM to set the default to echo off to to obviate the need for the ECHO OFF and CLS statements at the beginning of a batch file. DEBUG COMMAND.COM -E 1967<cr> xxxx:1967 01.00<cr> -W<cr> -Q<cr> Note 1: The default for AUTOEXEC.BAT files will still be ECHO OFF. Note 2: If the last thing done in a .BAT file is to do ECHO ON, then you will get two prompts at exit. The following is from Calvin R. Shields as reprinted in PC Mazazine Vol. 4 No. 4, p. 235 and will set ECHO OFF in your AUTOEXEC.BAT file. DEBUG COMMAND.COM -E 105B<cr> xxxx:105B 03.02<cr> -W<cr> -Q<cr> ********************************************************** BLANK LINES FROM ECHO This patch from Calvin R. Shields in PC Magazine Vol. 4, No. 4, p. 235 enables the ECHO command followed by two spaces to produce a blank line instead of returning the ECHO status. DEBUG COMMAND.COM -E 3878<cr> xxxx:3878 E8.83 20.F9 00.02 74.72<cr> -W<cr> -Q<cr> ********************************************************** FORMAT: Add BEEP at completion of formatting Stephen Berg provided a patch to FORMAT.COM in DOS 2.1 to produce a BEEP when FORMAT completes. The patch adapted to DOS 3.1 is shown below. The patch is most easily made with a disk editor. Using a disk editor look for the exact string: Format another (Y/N)? It begins at offset 142Fh (Note: This NOT a Debug address!) If you are using DISMOD, the address is record 0014 byte 2Fh Enter the following exact string (omit quotes), ^G means Ctrl-G: "Do another (Y/N) ?^G " (Note that one blank space follows ^G) If you wish to use Debug then: DEBUG FORMAT.COM -D 152F L20<cr> ;Displays "Format another..." -E 152F "Do another (Y/N) ?",07," "<cr> ;Quotes must be included -D 152F L20<cr> ;Displays your entry. -w -q The 07h (^G) does the BEEP. Below is what you should see after the first D command above. DEBUG FORMAT.COM -D 152F L20 xxxx:1520 46 F xxxx:1530 6F 72 6D 61 74 20 61 6E-6F 74 68 65 72 20 28 59 ormat another (Y xxxx:1540 2F 4E 29 3F 00 AF 0E 0D-0A 00 C7 0E 49 6E 76 /N)?........Inv ^^ ^ NOTE: THE 00H MUST NOT BE DISTURBED!!! ********************************************************** CORRECTION OF CLS COMMAND ERROR This patch from Calvin R. Shields in PC Magazine Vol. 4, No. 4, p. 235 corrects an error in the CLS command which presently clears 26 lines rather than the standard 25 lines on a display screen. DEBUG COMMAND.COM -E 263B<cr> xxxx:263B 19.18<cr> -W<cr> -Q<cr> ********************************************************* COMMAND.COM -- SOME UNDOCUMENTED FEATURES The following is from Bob Smith, author of 'Tall Screen'. EXPANDING THE PCDOS ENVIRONMENT AREA: A recent forage into DOS 3.1 COMMAND.COM uncovered the following seemingly supported, but undocumented feature: /E:NN Set size of Environment area to NN paragraphs. Range is 10 to 62 Numbers outside that range are ignored. The default is /E:10. This feature is most useful when used in conjunction with the SHELL= OPTION in CONFIG.SYS. In particular, my usage is as follows: SHELL=C:\DOS\COMMAND.COM C:\DOS /P /E:20 Other options include: /D Don't execute AUTOEXEC.BAT /F Skip response to ABORT, RETRY, IGNORE question in the System default INT 24h handler. (Quite likely this feature is named /F for 'FLAKY'.) A NOTE ON THE 'SHELL' COMMAND, ABOVE... The sample 'SHELL=' CONFIG.SYS command, above, shows several undocumented options available. In particular, the first parameter shows where the initial copy of COMMAND.COM is to be found (in the above example, on the '/DOS' subdirectory on the 'C:' disk). This is as documented by IBM. The second parameter indicates the drive and subdirectory from which COMMAND.COM is to be reloaded. Here again, the '/DOS' subdirectory on 'C:'. The '/P' parameter indicates that the substitution should be permanent. Note that in the DOS 3.10 REFERENCE MANUAL, the above two parameters are described for the 'COMMAND' command. What IBM doesn't tell you is that they also work on the 'SHELL=' command in CONFIG.SYS ----------------------- My thanks to Bob, Ward, and others for their patches. Comments to: -- Ted Eyrick [72446,317] CIS, IBMPC SIG -- Edited by: Jim Gainsley [76703,1007] (SysOp) IBMPC SIG CompuServe 8-9-85 9-2-85 ====================================================================== 2/20/86 IBM PROVIDES THE FOLLOWING PATCH FOR DOS 3.0 AND DOS 3.1 ------------------------------------------------------------------- DESCRIPTION: This patch corrects a condition where DOS is doing a test on bit 8 to determine if an error code returned from INT 13h should fall into the DMA boundary violation handler. This test is causing error codes other than DMA (09h) to fall into this handler. The patch changes this test to a direct compare. The patch corrects the same problem with each version of DOS 3. ____________________________________________________________________ The patch is made to the System file IBMBIO.COM. NOTE: The safest method of doing this is given in the last paragraph of this document. However, for those who feel sufficiently competant, and who don't wish to follow that course, the following method is presented. It will first be necessary to remove the Hidden/System/Read-only attribute, thus making the file a 'normal' file. AFTER you have completed the patch process, you MUST RESET this attribute to Hidden/System/Read-only. To work with the attibute, you can use the PD program CHMOD, or the Norton Utility Ver 3.1's FA.COM, Morgan Computing's DISKTOOL, or IBM's DISK REPAIR, a part of the PROFESSIONAL DEBUG package. You cannot use the DOS utility ATTRIB.COM. (Just for information, a 'normal' file attibute is either 00h or 20h, while a Hidden/System/Read-only attribute is either 07h or 27h. The attribute is one byte and is located in the Directory entry for the file, immediately following the last character in the filename extension. In this case, after the 'M' in COM.) See the documentation for whichever program above you've chosen to determine the procedure to be used. * * * * * * * NOTE: YOU ARE PATCHING THE HEART OF THE OPERATING SYSTEM... BE VERY CAREFUL!!! IF YOU THINK YOU MAY HAVE MADE A MISTAKE, EXIT BEFORE WRITING THE CHANGES AND START OVER AGAIN. Format a floppy using the command, FORMAT /S. Set the attribute for IBMBIO.COM to 'normal' as given above. Use the DOS utility DEBUG.COM, (or MicroSoft's SYMDEB), to make this patch. It is assumed that you are familiar with its use. Curiously, the patch changes only 4 bytes, though IBM indicates a 5-byte patch. ------------------------------------------------------------------- PATCH NUMBER: PATCH31.001 Use this patch if you have DOS 3.1: DOS LEVEL: 3.10 FILE PATCHED: IBMBIO.COM OFFSET OF PATCH: 09BB (Note: DEBUG address = 0ABB) NUMBER OF BYTES: 5 OLD CODE: F6 C4 08 75 0F NEW CODE: 80 FC 09 74 0F In what follows, Do not type the hyphens. The 'xxxx' mean 'don't care'. At the DOS prompt type: DEBUG d:\IBMBIO.COM <cr> where d: = drive containing IBMBIO.COM -D 0ABB L5 <cr> xxxx:0AB0 You should see OLD CODE given above starting at 0ABB. -E 0ABB 80 FC 09 74 0F <cr> -D 0ABB L5 <cr> xxxx:0AB0 You should see NEW CODE given above starting at 0ABB. -W <cr> Writing xxxx bytes -Q <cr> Patching complete. Reset the attribute to Hidden/System/Read-only. (At this point, you should consider bringing up the file again and and doing -D 0ABB L5, just as a final check). ---------------------------------------------------------------------- PATCH NUMBER: PATCH30.001 Use this patch if you have DOS 3.0 DOS LEVEL: 3.00 FILE PATCHED: IBMBIO.COM OFFSET OF PATCH: 0964 (Note: DEBUG address = 0A64) NUMBER OF BYTES: 5 OLD CODE: F6 C4 08 75 04 NEW CODE: 80 FC 09 74 04 In what follows, Do not type the hyphens. The 'xxxx' mean 'don't care'. At the DOS prompt type: DEBUG d:\IBMBIO.COM <cr> where d: = drive containing IBMBIO.COM -D 0A64 L5 <cr> xxxx:0A60 You should see OLD CODE given above starting at 0A64. -E 0A64 80 FC 09 74 04 <cr> -D 0A64 L5 <cr> xxxx:0A60 You should see NEW CODE given above starting at 0A64. -W <cr> Writing xxxx bytes -Q <cr> Patching complete. Reset the attribute to Hidden/System/Read-only. (At this point, you should consider bringing up the file again and and doing -D 0A64 L5, just as a final check.) -------------------------------------------------------------------------- TO UPDATE IBMBIO.COM ON YOUR HARD DISK: IMPORTANT!!! DO NOT USE DEBUG TO PATCH IBMBIO.COM ON A HARD DISK. 1. Complete the above, creating a floppy with the patched IBMBIO.COM, with attibute reset to Hid/Sys/Read-only. Then: Copy the DOS utility SYS.COM onto the floppy. Set the default drive to A: and put the floppy in it. Then type SYS C:<cr> (assuming your HD is Drive C:). You should then see the message 'system transferred'. YOU CANNOT SIMPLY USE DEBUG TO PATCH AN IBMBIO.COM THAT RESIDES ON A HARD DISK, BECAUSE DEBUG WILL NOT WRITE THE FILE BACK TO THE SAME SPACE ON A HARD DISK. IBMBIO.COM MUST RESIDE IN A SPECIFIC PLACE ON A DISK, and while DEBUG will write it back to the same place it came from on a floppy, it will not do so on a hard disk. * * * * If you're patching a hard disk and have a problem, you can always put your DOS System disk in Drive A:, boot it, and type SYS C:<cr>, which will replace the system files on the HD, provided of course that you haven't written anything to the hard disk before doing this. If you are not familiar with DEBUG, or simply don't want to monkey with it, then you may obtain the DOS 3 Patch Disk No. 1, from your dealer at no charge, (ask them to get it from Dealer Support if they don't have it). That disk contains an IBM program PATCH.COM, which will make the patch automatically. Since that program is not PD, we cannot post it. -- ihnp4------\ harvard-\ \ Mr. Video seismo!uwvax!nicmad!brown topaz-/ / decvax------/
mojo@kepler.UUCP (Morris Jones) (05/02/86)
This may start a debate. <sigh> In article <672@nicmad.UUCP> brown@nicmad.UUCP (Mr. Video) writes: > The CompuServe IBMPC SIG Users Group > ------------------------------------ > PATCHES FOR IBM DOS 3.1 > ----------------------- Posting this information violates the CompuServe copyright. CompuServe has explicitly reserved copyright to all information that you acquire on their system. In their current user agreements you are specifically enjoined from copying or retransmitting that information. They took this aggressive stand after users and sysops from competing services would "raid" the CompuServe SIG data libraries and make the files available on their systems. That doesn't mean I like it. And I can't decide what to do if I download something from CompuServe that states "Permission granted for distribution without profit ..." etc. CompuServe may not be the best place to distribute shareware. (sysop of MicroPro Forum...) -- Mojo ... Morris Jones, MicroPro Product Development {lll-crg,ptsfa,dual,well,pyramid}!micropro!kepler!mojo
gjs@faust.UUCP (05/05/86)
> The method that I have heard used is to first low-level format the > drive then FDISK it and then FORMAT it with PC-DOS 3.10. PC-DOS 3.10 > has been made so then the boot information is not overwritten, if it > is there. On my PC (not AT), I have successfully changed the cluster size of a 20 MB disk from 8 sectors to 2 sectors by deleting and creating the DOS partition with FDISK. Apparently FDISK writes the BIOS parameter block, not FORMAT. This avoids doing a low-level format. -- George Snyder -- Intermetrics, Inc. -- gjs@inmet --