gm@romeo.cs.duke.edu (Greg McGary) (01/01/89)
A friend has a True-Blue PC-XT with PC-DOS 2.10. I have a Hyundai 286c
with MS-DOS 3.30. Out of curiosity, I tried booting my MS-DOS 3.30
floppy on the XT, and it worked. I then got the bright idea that I
would try to make the XT's hard disk boot up with DOS 3.30. In that
endeavor I failed, and in the process managed to mangle the DOS system
stuff on the XT's hard-disk so that it won't boot from drive C:
anymore. It still boots fine from the floppy drive A: and the data on
the C: drive is fine. I looked through the DOS manuals and couldn't
discern any procedure less drastic than re-formatting the whole
hard-disk to make it bootable again. I tried running the `sys' command
to transfer the system files from the DOS 2.10 floppy to the hard-disk,
but no go.
So, I have two questions:
* Can I truly accomplish my original goal of `upgrading' to DOS 3.30
bootable from C: & if so, how?
* If that won't do, how can I restore DOS 2.10 to bootability on C:
without having to reformat the disk?
Don't hesitate about giving me the gory technical details--I've been
a UNIX kernel hacker for a number of years, so I can take it. Up until
now, I've managed to totally ignore everything about DOS, so that's why
I'm doing and asking about stupid things...
By the way, of the zillions of books on the shelf purporting to tell me
about the naughty bits of DOS, which ones are the best?
Thanks!
-- Greg McGary
-- 4201 University Drive #102, Durham, NC 27707 (919) 490-6037
-- {decvax,hplabs,seismo,mcnc}!duke!gm
-- gm@cs.duke.eduward@chinet.chi.il.us (Ward Christensen) (01/03/89)
I've done no exhaustive study of this (I never DO exhaustive studies ;-) but I have determined some tricks to make SYS work without reformatting - but of course these ARE "advanced topics" as you said you would handle: Using something like Norton Advanced Utilities, ensure that (1) there are sufficient clean clusters @ the front of the disk, i.e. if IBMBIO and IBMDOS are a total of (making this up...) 34 clusters long, be sure clusters 2-36 are open. At leeast in some early DOSs, they HAD to be contig. Then make sure the first 3 directory entries are not only available, but ZEROED. I believe I zeroed the first 4 (not sure 3 is enough). Then boot the floppy and sys the hard disk. Also make sure FDISK has the partition flagged as "active" - that is the single most common reason an "otherwise OK hard disk (accessible from A: booted floppy)" won't boot. CAUTION: zeros in the first byte of any directory entry signals DOS "end of directory". CHKDSK also sees it as the end. SO be sure to go back and patch in an E5 so the remaining dir entries will then again be seen. These hacks have always worked for me - SYS seems to say "OK, the space is open, the directory is empty, GO FOR IT" when in fact you were just "kidding it" in a non-destructive way. "For advanced hackers only - not responsible for mistakes YOU make or any I may have made in describing this technqiue" ;-)
sl148033@silver.bacs.indiana.edu (Kevin_Clendenien) (01/03/89)
In article <13186@duke.cs.duke.edu> gm@romeo.cs.duke.edu (Greg McGary) writes: >* Can I truly accomplish my original goal of `upgrading' to DOS 3.30 > bootable from C: & if so, how? > >* If that won't do, how can I restore DOS 2.10 to bootability on C: > without having to reformat the disk? I don't know about DOS 2.10, but with DOS 3.30 you would use the FDISK command. When you put DOS 3.30 onto the harddisk, did you also leave DOS 2.10 on the harddisk? Anyway, there is an option inside of FDISK to make a partition active. This is how you specify which partition you want to have the harddisk boot. So, if you had several operating systems on you harddisk, you would have to specify a particular partition as active before it would boot. Try using FDISK to make your DOS 3.30 partition active, and then reboot the computer. -------------------------------------------------------------------------- sl148033@silver.UUCP Kevin B. Clendenien --------------------------------------------------------------------------
root@gsy1.UUCP (Scott Yates N4BBB) (01/06/89)
In article <13186@duke.cs.duke.edu>, gm@romeo.cs.duke.edu (Greg McGary) writes: > A friend has a True-Blue PC-XT with PC-DOS 2.10. I have a Hyundai 286c > with MS-DOS 3.30. Out of curiosity, I tried booting my MS-DOS 3.30 > floppy on the XT, and it worked. I then got the bright idea that I > would try to make the XT's hard disk boot up with DOS 3.30. In that > endeavor I failed, and in the process managed to mangle the DOS system > stuff on the XT's hard-disk so that it won't boot from drive C: > anymore. It still boots fine from the floppy drive A: and the data on > the C: drive is fine. Greg, I believe the problem is that dos 3.0 and above use 2k minimum disk allocation units, and that 2.11 dos uses 8 k. A 1 byte file under dos 2.xx will use 8k of disk space. This is the 'slack' that Norton Utilities reports in disk usage. One of the improvements incorporated in version 3.0 and above is the minimum disk allocation of 2k. Much more efficient way of handling file space. To make the most of the upgrade, re-low-level the HD, create the partition, and reformat with system (/s). -- Scott Yates, N4BBB o o DOMAIN: gsy@gsy1.UUCP || gsy@raider.UUCP Yates Pest Control \ / UUCP: ...!{ames,rutgers}!killer!mjbtn!gsy1!gsy Rockvale, Tennessee (OO) FIDO: Scott Yates at Net/Node 1:116/12 / 1:116/9 "Bugs are my Life!" <> VOICE: (615) 274-2156 / (615) 459-2636