• Please review our updated Terms and Rules here

Maxtor 7120AT jumper settings.

That was a good suggestion. I jumpered it, and BIOS keeps its settings... However, now instead of booting to "No boot device available", it boots to an error message that says "Missing operating system." My gut tells me this is a bad thing. Does this mean the drive has somehow been corrupted in the last 30 years and there's no data on it left to recover? Or is there still some slim hope that something's misconfigured and it can't find the master boot record?
If I look on an early computer of mine that has a hard drive loaded with IBM DOS, the error message of "Missing operating system" is in the boot code of master boot record. So, indications are that your motherboard's BIOS has decided to boot from the hard drive by executing the boot code there. That boot code inspects the partition table, and then what it does depends on the contents of the partition table.

"Missing operating system" could be caused by the wrong hard drive settings.

What I am seeing for a Maxtor 7120AT is as follows:

1694900947491.png
 
Regarding my previous post, specifically the 'CMOS SETTINGS' column.
That may be a 'recommended' type thing.
Certainly something to try.
 
I do not have such a boot disk. Ordered floppies and an A: drive, they'll be here tomorrow.
So this 486 does not have a floppy drive in it ?
What size floppy disks have you ordered 3.5" 720k or 1.44Mb or 5.25" 360k or 1.2Mb
What size floppy drive have you ordered 3.5" or 5.25"
I assume you have no other old computers ?
 
Apart from the 486 what other computers do you have, Oldest first and what OS does it run
Just trying to get an idea of what hardware you have, It's an easy enough task if you have the hardware but a pain in the butt if you don't.
 
I have a laptop and a desktop running Windows 10.

Received floppy disks and drive. If you suggest making a boot disk, please let me know where to get the files.
 
Last edited:
I ordered 3.5" 1.44Mb floppies and a 3.5" USB A: drive
That will be good.

For example, if, on my IBM AT, I run the Disk Editor tool of Norton Utilities to view the partition table on the hard drive, I see what is shown in the image below.

Based on that, and assuming that the partition shown ends at the final sector on the final track, I can make the following deductions about what hard drive 0 was setup in CMOS SETUP:
- About 614 cylinders (0-613)
- 4 heads (0-3)
- 17 sectors/track (1-17)

If I go into CMOS SETUP, I see that it is set to an IBM type 2 drive, which equates to: 615 cylinders, 4 heads, 17 sectors/track

The reason for the difference between 614 and 615 cylinders is because DOS 3.3 is not using the final cylinder, which will be because the final cylinder is typically reserved for diagnostic use.


1694989280061.png
 
Here? https://www.allbootdisks.com/download/dos.html

I dunno guys. I appreciate all the help, but I'm getting defeated at every turn here. I can format the floppy through Windows 10 My Computer, but hell if any of these DOS boot disks will let me write to the floppy. ¯\_(ツ)_/¯

error0.png

error00.png

error1.png

error2.png

Tried using a different floppy, cycling write protect slider on the floppy, rebooting Windows, running Dos6.22 as administrator, disabling Windows 10 Defender real-time protection, replacing child object permissions with inheritable permissions, disabling UAC
 
Using my WIN10 computer, I get the same errors.
Workaround:

1. Using a command prompt in Windows, format a 1.44M diskette.

2. Download the .IMG file (1.44M sized) instead of the .EXE

3. Install WinImage software. ( I have version 10 on my computer. )

4. Per the following, use WinImage to write the .IMG file to the pre-formatted target 1.44M diskette:

- In Windows Explorer, double-click on the downloaded .IMG file. As a result, WinImage should open, showing the contents of the image file.

- On the WinImage menu bar, select DISK and in the menu shown, verify that the drive selected is your 1.44M one.

1695074630821.png

- On the WinImage menu bar, select DISK and then WRITE DISK. WinImage should start writing to the pre-formatted diskette.
 
I'll work on getting the disk written. Assuming I'm successful and I'm able to boot from it on the 486, what exactly would you like me to check? What commands would you have me run from DOS?

Edit: Error attempting to write disk from WinImage, tried multiple times on multiple floppies

error.png
 
Last edited:
Edit: Error attempting to write disk from WinImage, tried multiple times on multiple floppies
I see from [here] that others have seen the 'Floppies do not match' error message of WinImage.

Q1. Is it always 'track 33, sector 1' ?

Q2. In the instructions within post #53, I get you to format the 1.44M diskette using a Windows command prompt. Is that bit working ?

Q3. If the answer to Q2 is yes, WinImage requires flawless (no bad sectors) diskettes. Below I show how to identify Windows 10 pointing out bad sectors. Seeing those ?

1695083719505.png
 
I'll work on getting the disk written. Assuming I'm successful and I'm able to boot from it on the 486, what exactly would you like me to check? What commands would you have me run from DOS?

Activity #1

After booting from the DOS boot diskette, you will end up with an A: prompt.
Enter dir c:

It will be interesting to see if something intelligible is shown. Note that not seeing something intelligible does not mean that your drive is bad, or has faulty content.

Activity #2

1. Acquire Norton Utilities 6.
2. In that is the disk editor tool. It will be named DE.EXE or DISKEDIT.EXE
3. Copy DE.EXE (or DISKEDIT.EXE if that is its name) onto the DOS boot diskette.
4. Boot from the DOS boot diskette.
5. At the A: prompt, enter DE or DISKEDIT, as applicable.

Disk Editor runs.

6. On the menubar, select 'Object' (e.g. use ALT-O).
7. Use the arrow key to move down to the 'partition Table' option.
8. Press ENTER key.

The partition table should be showing, like the example shown in post #50 above.
Send us a photo of that.
 
Q2: I formatted the floppy again. It seems to be fine, as far as I can tell.

format.png

Q1: It isn't always the same. I tried again, and this time I get this error:

error.png

If I click ignore, the disk continues formatting, ticks up another few percent, and then gives this error:

error2.png

At 59%:

error3.png

I guess I can keep hitting ignore, theoretically? Not sure what the consequence is to the data on the diskette.

After hitting ignore about eight times, the disk finishes writing. Here it is in Windows explorer:

a.png

Looks like it isn't bringing over all the files. Missing: MSDOS.sys, IO.sys, DRVSPACE.bin, CONFIG.sys, COMMAND.com, AUTOEXEC.bat

I'm not sure how I would have room on the same diskette for DISKEDIT.EXE.
 
Last edited:
If I click ignore, the disk continues formatting, ticks up another few percent, and then gives this error:
The 'Ignore' option would for advanced users. There are sure to be consequences. Accordingly, I would not be trusting the contents of target diskette.

I'm not sure how I would have room on the same diskette for DISKEDIT.EXE.
That image contains a lot of stuff that you do not need for the task. For example, if you delete the two QBASIC (Quick BASIC) files and the SCANDISK files, that frees up significant space.

And you can do that deletion within WinImage, before you use WinImage's 'WRITE DISK'.

The question as I see it is, is this a WinImage issue of some kind, or other software (e.g. antivirus), or is it hardware (drive/diskettes), or is it Windows 10. If you use the drive via Windows Explorer, does it function okay, e.g. copy close to 1.44M worth of files to it, then copy those files back. If things don't work via Windows Explorer, I don't think we can expect WinImage to work properly.

Another possible path: An image file that has only the files on it required to boot to DOS. That's not much. Since the 'Floppies do not match' error seems to be happening on random tracks, multiple attempts using the 'bare bones' image file may result in something that is usable.

I have a laptop and a desktop running Windows 10.
If that is a USB based 1.44M diskette drive that you have acquired, have you tried it on both computers ?
 
FYI

As I wrote before, like you, I am using Windows 10.

I upgraded my WinImage from version 10 to 11. (64 bits)

I then downloaded the dos3.3.img file from [here] and then successfully used WinImage 11 to write dos3.3.img to a 1.44M diskette.

( My anti-malware software is Panda Dome, and I did not need to temporarily disable it. )
 
Back
Top