Isn't this what the SYS.COM utility is supposed to do? FORMAT A: /S == FORMAT A: + SYS A: ? --Patrick

THIS I did not know! Maybe SYS would work after all! Great tip, Pat! --Patrick

On Mon, 12 Apr 2004, John Allain wrote: The older boot sectors loaded IO.SYS (IBMBIO.COM for PC-DOS) as first entry, using the cluster mapping found for the first entry in the root directory, and then the same for MSDOS.SYS (IBMDOS.COM for PC-DOS) using the second entry in that root directory. I do remember there was some level of magic checking- but afaik, they took that out fairly quickly. So, assuming a blank diskette: 1. Format it with FAT(-12) 2. Make *sure* the first two directory entries are blank, which includes no volume label being present (== dir entry !) 3. Copy those two files over. 4. Patch the boot sector. 5. Copy COMMAND.COM and any other files. This has always worked for me. But, yeah, as someone already pointed out, it is much easier to just archive bootable images of these diskettes :) --f

Hi John, Sorry that I'm late checking in; I've got a bad teaching schedule) The biggest problem that shows up is that the boot sector is slightly different for a bootable disk, and the two hidden system files must be in certain places AND must be the first two DIRectory entries, rather than being controlled by the usual DIRectory data. Thus, it is very difficult to add bootability once any files are written to the disk. The SIMPLEST and EASIEST way to be able to produce bootable floppies of multiple DOS versions is to keep a write-protected bootable floppy on hand of each and every version. Then, when you need a disk, DISKCOPY the bootable floppy onto the blank, instead of FORMATting it. (Or, if you have multiple floppy drives, the newer versions of SYS.COM [starting with which version?] will permit you to FORMAT and then SYS B: A: (early versions of SYS could only SYS a diskette with version of DOS that was currently running)) That way (keeping a collection of floppy samples), you never need to reboot your machine into a different version (which could lock you out of access to hard disk, etc. since DOS <3.31 can not comprehend volumes > 32M) You do NOT need two floppy drives to DISKCOPY. If you ask for DISKCOPY A: A: then the system will prompt you to swap the diskettes. On earlier versions of DOS/DISKCOPY, that can mean a LOT of swapping. But you CAN DISKCOPY an early diskette with a more current version of DOS/DISKCOPY running. The down side of that technique is that you need to store a few dozen floppies. If you use SYS, then you COULD use a hard-drive partition for each version. If you are willing to use non-MICROS~1 software, then there are programs that will permit storing a diskette image and writing that to floppy, which would permit storing images of your collection of boot disks, rather than physical floppies. You could also do that using DEBUG (the most powerful program to ever come from MICROS~1). Figure out how much of a bootable floppy is actually used (for the sake of the following, let's call that 64 sectors) With the bootable floppy for version x.yz in drive A:, type: L 100 0 0 40 (Read 64 physical sectors (64 = 40h) from A:) N C:bootdisk.xyz (arbitrary naming scheme) R CX (set size) 8000 (64 sectors holds 32768 bytes = 8000h) W (save 8000h bytes to file To create a boot disk (from a FORMATted disk): N C:bootdisk.xyz (select file) L (load file) W 100 0 0 40 (write to physical sectors of floppy) NOTE: when learning DEBUG, you will probably accidentally erase your harddisk. We will not be responsible for errors. If you are dealing with diskettes that are NOT MS-DOS formats, then you need to use other techniques. -- Grumpy Ol' Fred cisin(a)xenosoft.com

On Mon, 12 Apr 2004, John Allain wrote: MSDOS PCDOS machine-specific IO code IO.SYS IBMBIO.COM Microsoft-provided OS code MSDOS.SYS IBMDOS.COM Probably vestigial from very early machines that could not boot 360K diskettes, only 320K? 5" diskettes went to 9 sectors/track some time after the machine's release, I forget the PCDOS version. The 8spt was a very conservative choice, in fact a little odd, as the 9th sector always fit. There were four diskette flavors, single and double sided, 8 and 9 sectors/track. Clearly only double-sided/9spt survived. (My personal MSDOS 3.x machine was a multibuss box with 8" drives that took all the standard permutations but also a 1024 byte 9 sector format that gave me a LOT of storage, nearly 1.5Mbytes/diskette. Wowee zowee.)

Duh. Ignore this--wrong path. I see what you are trying to do, John. (More caffeine please.) My approach to this is to make base bootable floppies in the same (slow) way in which you did (reboot to bootable partition or floppy with the target version). Then, using whatever tools you like (dd, teledisk, fdimage, copyflop, etc), make an image of the bootable disk and stow it away. When you want a bootable disk in that flavor, create it from the image, and then copy whatever additional files you need. Using dd on *nix is particularly handy, because you can archive all kinds of formats--I use it for boot disks for 3Com terminal servers, an old voicemail system, etc. --Patrick

On 12 Apr 2004 at 12:03, John Allain wrote: Step 2 is "install a DOS boot sector at cylinder 0, head 0, sector 1 of the floppy." This is normally done automatically by the "format" command, but the format command for a given OS will install a boot sector for that OS, e.g., if you're running NT, the NT format command will install an NT boot sector, i.e., one that tries to load NTLDR. Copy the boot sector (512 bytes) from a known bootable DOS diskette to a file on your hard drive. Then, to make a new diskette DOS-bootable, copy the boot sector file to logical sector 0 of the floppy as "step 2" of your process. You didn't mention what your "higher-version OS" is, but if you're running one of the Win9x-series, or WinNT up through version 4.0, you can run a small "debug" script to copy the boot sector. This one will copy from the floppy to the file "c:\bootsect.dos": L 100 0 0 1 N C:\BOOTSECT.DOS R BX 0 R CX 200 W Q ...and this one will copy it back to a floppy: N C:\BOOTSECT.DOS L W 100 0 0 1 Q (This will work under NT 4.0 as well if you're logged in as "Administrator". I don't believe that it will work under Win2K/XP, as direct floppy writes from "debug" seem to have been disallowed even under the Administrator account, although I haven't investigated thoroughly.) -- Dave