Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!mit-eddie!uw-beaver!zephyr.ens.tek.com!tektronix!nosun!qiclab!techbook!fzsitvay From: fzsitvay@techbook.com (Frank Zsitvay) Newsgroups: comp.sys.ibm.pc.misc Subject: DOS is DOS ?? Message-ID: <1990Sep8.134722.4843@techbook.com> Date: 8 Sep 90 13:47:22 GMT Distribution: usa Organization: TECHbooks of Beaverton Oregon - Public Access Unix Lines: 97 In article <1990Sep5.171921.14940@cbnewsh.att.com> europa@cbnewsh.att.com (r.j.capik) writes: > > Here is a question that I can't seem to find an answer for > and don't even have a clue where (else) to look. The question: > What is the difference between DOS? To be a bit more specific, > what do vendors do to DOS and how can one evaluate the > differences. > I've encountered an unreasonable number of odd problems that > can for the most part be traced to some *magic* that a vendor > has added to their DOS. However, even without added magic > different DOS versions seem to have unpredictable results. > In one upgrade; hard disk #0 (normaly drive C:) became drive > D: and disk #1 became C: (with a read error). FDISK showed no > DOS Partitions on disk #1. Re-boot (same versio, different > vendor) and both disks are back, but now I get interupt errors > that I didn't have before. Microsoft is one of those companies that knows a buck when they see it, and will do almost anything to sell their operating system, including allowing the hardware manufacturer to tailor the operating system to the hardware, instead of doing it all in the BIOS. (there are some arguements in favor of this sort of thing, but i don't want to get into that. Something that is quite common is mapping the interrupts physically differentthan in the original ibm, and rerouting the interrupts in the operating system so that everything works fine as long as you use that custom version of dos in that machine. i don't understand there to be any technical advantage to doing this, but some manufacturers want to be different. (not invented here syndrome.) zenith is very good about doing this. compaq modified dos so that you could have hard drives larger than 32 megabytes. handy for those with 300 megabytes drives who don't want drive designators spanning from a: to l:, but creates its own incompatibilities when that one piece of software that comes down the pike does something the designers at compaq never dreamed of. others have modified DOS so you would have more than 640k TPA, only to find that such mods would create havoc when the machine it was running on was upgraded to VGA. and of course there are those companies that some time ago marketed semi- compatible machines, like DEC's Rainbow, which i consider to be one of the "left feild" orphans. not only is the interrupt structure screwy, or the floppy disk format screwy, or the bios screwy (IT HAS NONE!!!), but it runs a funny version of the operating system as well. (a bastard mod of dos 3.1, which packs along its own bios on disk.) I really shouldn't slam the rainbow as much as i do (i'm using one to write this) because it does have its good points. (when chkdsk reports 800k ram free, i still snicker at those stuck with less that 600k free.) > I did an upgrade on another system (DOS 2.2 to DOS 3.0) > where I backed every thing to another hard disk. I upgrade the > 1st disk only to find that I can no longer read the 2nd disk > (the one with my full backup). It turns out that the new version > can't read the old hard disk format, BUT, the old version can > read both the old and the NEW format. So go figure... when dos jumped from 2.xx to 3.xx, some stuff was added to the hard disk format in such way that 2.xx could find what it needed, but no provision was made in 3.xx to read the 2.xx format. the guys at microsoft probably never anticipated that happenning, and so saved a few bytes leaving it out. (in other words, 3.xx needs information from the disk that 2.xx never wrote and as such thinks it's an error in the media. > I did another upgrade on another computer (DOS 3.3 to DOS > 4.0, and a tape backup). Install the new DOS, OK. Down load the > old files, OK. Use some programs, OK. Edit a file: ERROR can't > find ROOT directory! Copy some files to another directory: ERROR > can't find ROOT directory! I run CHKDSK, Norton, Mace, etc. and > everything is fine, no errors found. Re-install DOS 3.3, and > every thing is back to normal. dos 4.xx is still too buggy for many uses. it changed a considerable amount of things in the hard disk format (to allow drives greater than 32 megs) which makes it a necessity to reformat your hard disk. even then, i know people who wish they never heard of 4.xx because a bunch of their software wouldn't coexist with it. > I got a data disk from a friend (Lotus123 WKS files) where > the files were created on a HP machine. All my DOS machines can > read the disk fine, but Lotus gives me a file error, and once > more CHKDSK shows no errors. Then magic of magic, I try the disk > on a Macintosh with a DOS reader, and all the data is there just > like it should be (but I have no idea how to move it from the > Mac to a normal computer). different versions of lotus?? perhaps the creator used a lotus lookalike?? -- fzsitvay@techbook.COM - one of these days i'll get it right... Version 2 of anything is usually the version that works.