View Full Version : OT? Computers

12-02-2003, 12:18 PM
The computer that I have to run the small CNC mill and lathe that I use for medical device prototypes died. The program run on DOS. It may have something to do with the hard drive. Are there good books out there that I can get to upgrade my basic knowledge about computer hardware and fault finding.
Much appreciated.

Excitable Boy
12-02-2003, 12:37 PM
PC Upgrade and Repair by IDG books. It's a $50.00 investment once but since buying my copy years ago, I haven't had to pay someone to work on one of my machines since.


Pursue Excellence and the rest will follow.

12-02-2003, 07:36 PM
You speak of Scott Mueller's books? I agree, i have most issues from 2 though 13. Each is better than the last. Barnes and Noble carries the book. Got buy a cup of coffee, find a chair and read. The book is good for physical repairs and upgrading. I like the O'rielly "Nutshell" books for software problems. Mueller keeps his books up to date with revisions- but a four year old computer and a three year old book are in date. Go for it!

12-04-2003, 03:15 AM
If you could describe the problem maybe myself or Evan could help you oout with it...

12-04-2003, 03:34 AM
Programs like that which run in DOS usually will run on a 486. Those are a dime a dozen. Try looking for one at a computer store that does a lot of repair work. If you came to my store I could fix you up with one, cheep.

[This message has been edited by Evan (edited 12-04-2003).]

12-04-2003, 11:44 AM

[This message has been edited by pgmrdan (edited 03-08-2004).]

12-04-2003, 12:44 PM

DOS 6.22 was the last version of Microsoft "real" DOS. Windows 95A contains a kneecapped version known as DOS 7.0. DOS 7.0 is still "real" DOS but some of the functions were left out. There is also DRDOS from Digital Research that is compatible. If you can find an old 486 with working hard drive it will have DOS on it. Then make a floppy bootable with the sys command and copy DOS to the floppy, picking only the commands you need. You can just about fit the whole works on a floppy. There is no real installation for DOS. You can copy the DOS directory to any machine with a bootable HD and the correct config.sys and autoexec.bat and away you go. You need a boot floppy disk with the same version of DOS on it to set up the hard drive as bootable using the sys command since the command.com and io.sys files must be the same version level as the DOS. You could even just run from the floppy as nearly all of DOS will fit on a floppy if you scrap the unnecessary help files and commands.

DOS 6.22 can theoretically address a Hard Disk Drive of up to two tera-bytes, BUT, The only problem is the 16 bit FAT used by DOS and older Windows (3.1, 95A)operating systems, lowers this limit to 2.1 GByte. However, most 486 vintage motherboards can only access a drive up to 528 megabytes so take that as the size limit. The drive can be partioned up to four partions so you could use up to a 2 gig drive. There are other solutions such as drive manager software but you don't need more than that anyway.

As for RAM, motherboard limitations will determine how much ram you can use. Even the 386DX processor can theoretically access up to 4GB of ram. This is not really an issue since most of the programs probably won't need more than one megabyte of ram.

12-04-2003, 12:58 PM

[This message has been edited by pgmrdan (edited 03-08-2004).]

12-04-2003, 02:21 PM
No I haven't but it would probably work fine.

12-04-2003, 07:52 PM
Evan and Thrud:
Thank you for your offer of diagnosting my problem. Both computers have not been used for some time. Both are Gateway 486 types. One older than the other. The older one a 4DX-33 shows that the hard drive cannot be found or the cables are disconnected. Checked the cables and it seems that they are ok. The other computer shows that the operating system is missing. I have the disks for DOS 6.22. They do seem to load up in the newer computer. I think it's time for an upgrade. A friend would check the better one and replace parts if necessary. The price is right.
Thanks again for your offer. I'm not much of a contributer to this forum but have learned a lot. Who said you can't teach an old dog new tricks.