Path: utzoo!utgpu!watserv1!watmath!att!att!pacbell.com!ames!sun-barr!cs.utexas.edu!uunet!comp.vuw.ac.nz!csc.canterbury.ac.nz!cctr132 From: cctr132@csc.canterbury.ac.nz Newsgroups: comp.sys.ibm.pc.misc Subject: Re: question about dos Message-ID: <1990Nov29.161558.10038@csc.canterbury.ac.nz> Date: 29 Nov 90 03:21:42 GMT References: <1990Nov26.172206.244@eng.umd.edu> <1427@tnosoes.izf.tno.nl> <1990Nov28.131211.10020@canterbury.ac.nz> <1990Nov28.223852.12623@sj.ate.slb.com> Organization: University of Canterbury, Christchurch, New Zealand Lines: 68 Sorry about the extensive quoting of previous posts, but it kind of sets the scene. In article <1990Nov28.223852.12623@sj.ate.slb.com>, poffen@sj.ate.slb.com (Russ Poffenberger) writes: > In article <1990Nov28.131211.10020@canterbury.ac.nz> cctr132@canterbury.ac.nz writes: >>In article <1427@tnosoes.izf.tno.nl>, joris@tnosoes.izf.tno.nl >>(Joris Linssen) writes: >> >>> yun@eng.umd.edu (Dragon Taunter) writes: >>> >>>>I have been handed down an old AT with 512K ram. It has a full hard >>>>disk which I do not want to overwrite. How do I upgrade to a newer dos? >>>>I suspect that there is more to it than copying over everything in /DOS >>> >>> Well, this is supposed to be easy: >>> >>> 1. Boot your computer from floppy with the new DOS version. >>> 2. After confirming date and time enter SYS A: C: from the command line. >>> This will transfer two hidden files from floppy to hard disk. >>> 3. Copy the DOS utility files from A: to the system subdirectory on your hard >>> disk, for example C:\DOS >>> 4. Say a quick prayer and reboot you computer from hard disk. Normally this >>> works (but then, when does something work normally in a DOS environment :-), >>> but should a problem occur, you can always restore your old version with >>> the same procedure. >>> 5. In case of trouble contact your local DOS whizard, >> >>Good advice *EXCEPT* step 2 should also include the instruction: >> COPY A:COMMAND.COM C:\ >>This definitely needs to be done up to (MS) DOS 3.3 (some OEM versions may >>have SYS copy COMMAND.COM automatically) - don't know about DOS 4, as have >>never installed it. >> >>Without copying the new version of COMMAND.COM to your hard disk, you will >>get a "Bad or missing command interpreter", or some such, error message. >> > > I is possible that you will need to use Norton Utilities or something similar > ro make sure there is enough contiguous space for the two new boot files that > must reside in contiguous blocks at the beginning of the disk. Since the new > DOS has larger boot files (probably), and the disk blocks after the existing > boot files are probably being used by other files, then sys C: will probably > fail. This whole area is shrouded in myth/mystery. As I understand it (and I may well be wrong), Russ is correct for versions of DOS pre-3.0, and possibly for 3.0 (maybe even 3.1?), but somewhere around ver 3.0/3.1 MS reorganized the code of IO.SYS and MSDOS.SYS so the file-handling calls were loaded earlier (first?) than in previous versions. This allowed the system files to be non-contiguous, after a certain portion of them had been loaded. It may also have removed the requirement of MSDOS.SYS being the second entry in the root directory of the boot disk - I'm not so sure about this. Confusion over what has to be where on a system disk, and how to insure that all is right are frequently the source of questions to this and related groups. (A couple of months back someone advised an inquirer with a question similar to the poster who started this discussion, that s/he would *have* to low-level format their disk.) Anyone who knows the full story care to throw some light on this?? --------------------------------------------------------------------------- Nick FitzGerald, PC Applications Consultant, CSC, Uni of Canterbury, N.Z. Internet: n.fitzgerald@csc.canterbury.ac.nz Phone: (64)(3) 642-337