Boot from MFM disk drive - How to install DOS?

[Dallas_Green]

Hello all

I wanted to get my MFM disk drive bootable in order to get rid of the floppy but I always end up with the following message, when it attempts to boot from:

Error loading operating system from fixed disk.

Insert COMPAQ DOS diskette in drive A.
Press any key when ready: _

What I did was:
- boot DOS from floppy: COMPAQ Personal Computer - MS-DOS v2.12 Rev. B
- low level format
A:\>debug
G=C800:6
- create primary partition with fdisk
- format partition
A:\>format c: /s

I also tried to copy the files then manually to the drive. The result was the same.

sys c:
md c:\dos
copy a:\ c:\dos
copy a:\command.com c:\

None of this worked.
Has anyone an idea how to make the drive bootable? Or it seems that it is somehow bootable but cannot execute the command.bat.

The HDD is a Rodime RO250 with a OMTI controller. It's the same behavior on a 386/286 like on the origianal Compaq portable, alltought I didn't try to format/install dos from the compaq yet. Just tried to boot from there. But I assume that it doesn't really matter with which machine the OS has been installed, does it?

Thanks and regards
Dallas

 

[Timo W.]

Did you mark the partition as being active in fdisk? Otherwise, it is not bootable.

 

[Dallas_Green]

Yes, its already aktive.

 

[Timo W.]

Maybe give it a try using fdisk from MS-DOS 5 and do "fdisk /mbr" afterwards.

 

[Dallas_Green]

Hello all

I could solve a little bite the issue by creating 2 partitions on the hard disk. It seems that there is something wrong with cylinder 305/600. I formatted the drive with dos 3.3 and there it tells you the current cylinder formating and stopped at that mentioned point. In dos 2.12 there wasn't this message displayed.

So I created a primary partition just until cylinder 300, made "format c: /s" and copied the rest of the files in a folder "dos" an everything worked well so far.
From that point on the drive is bootable on my 386.

Unfortunately on my Compaq Portable 1 not. It just stucks after the post beep, showing: _

Is there a difference how the drive needs to be formatted in order to be readable with the Compaq portable, 8088 CPU? Or maybe there is something incompatible with the MFM controller? But if yes why did it then show before the message from post #1, when the partition was invalid? So I assume that it could access to the drive somehow even when it couldn't boot that time.

In case it matters I low level formatted the MFM drive before on my 386 with:

- debug
- G=C800:6 (since its an OMTI controller)

Unfortunately I cannot try to boot/format from a on the protable yet since there is something broken with the floppy disk controller. So I was going to bring it to life using the hard drive ;-)

Thanks in advance
Dallas

 

[Svenska]

MFM drives are not transportable across controllers. You need to low-level format with the particular controller you are going to use.

 

[Koolstar42]

Maybe you could benefit from using hTest-hFormat from Kolod research. I have version 2.1 (attached)
It comes with an extensive manual, of which I do not have a digital copy. Maybe you can find it somewhere on the web.

 

[modem7]

Some days ago, I had an offline discussion with the OP.

The BIOS ROM in his OMTI 5520 MFM controller does not match the BIOS behaviour shown in the 5520 manual that he found online. That is, removing the W1-W4 jumpers does not result in 'dynamic formatting' capability.

Therefore, the W1-W4 jumpers need to be set to match his Rodime drive, and it is unknown as to whether or not the BIOS ROM on his controller supports the CHS geometry of that drive.

I advised the OP to try SpeedStor with its /romlist switch, to see if SpeedStor will display the drive table within the controller's BIOS ROM.

If the CHS geometry of his Rodime drive is not supported, I said that I should be able modify the drive table in the controller's BIOS ROM so that the Rodime drive's CHS is in every entry of the table, meaning that the first W1-W4 jumper setting can be used.

I think this is the way to go; first, get the controller 'happy' about the attached drive, then proceed to low-level format, etc. (on the Compaq Portable).

 

[NicolasF]

You could use DEBUG to load the MBR sector and then check if it has the 0x55 0xAA flag at the end. I think the command is "L 100 2 0 1"

 

[Dallas_Green]

Hello all, good evening

First I'd like to say sorry for not having responded anymore. I had to take a week off.

As @modem7 mentioned we already had a private conversation about. Thinking about this again it would have been better if I would have put it here instead. However the situation is that I could low level format the drive with the controller on my AT and its already bootable there after HLF. The thing is that by putting controller + drive now into my XT (Compaq Portable) its not booting and it seems that there is like a conflict between the PCB BIOS and the controller but this was just an idea. Like @modem7 said the next step would be to make sure that the controller is configured properly regarding the the drive specification. Since there isn't any prompt for that by low level formatting, we are assuming that the controller needs to be configured through the correct jumper setting. I already did that like explained here but it seems that the controller has some kind of "special" BIOS version with other drive specification then mentioned.

Since my XT isn't working yet because of a defective floppy controller I cannot execute sstor there in order to get the supported drive characteristics. I just gave it a try on my AT but @modem7 already warned me that the behavior of the controller could be different on the AT since it was actually designed for XTs only.

sstor /romlist on the AT: It seems that the drive is not supported. At least the first one from the list is quite equal.

Drive: Cyls=306 Heads=4 Sec=32 Pcomp=123 Lzone=305
Controller Cyls=306 Heads=4 Sec=17 Pcomp=123 Lzone=305

Could this be an explanation why during high level formatting it shows about 612 cylinders to be formatted and always fails at cylinder 302 if I'm not creating a partion with 300 cylinders only?
I'm afraid for a test with the XT I would have to get my floppy drive controller fixed first. This is one of the reasons why I'm trying to get the fixed disk working (Is there a good thread somewhere with some help about?)

@modem7, do you think the sstor output on the AT is reliable in order to adapt the BIOS of the controller?

Thank you very much in advance,
Dallas

 

[Dallas_Green]

This is the content of the EPROM on the OMTI controller.

 

[modem7]

sstor /romlist on the AT: It seems that the drive is not supported. At least the first one from the list is quite equal.

Drive: Cyls=306 Heads=4 Sec=32 Pcomp=123 Lzone=305
Controller Cyls=306 Heads=4 Sec=17 Pcomp=123 Lzone=305

Because you ran that on an AT-class computer, SpeedStor might have showed you the drive table in the motherboard's BIOS (because that is where it resides in an AT-class computer).
In the OMTI 5520A's BIOS ROM, there are only 16 drive entries.
If you saw more than 16, then you probably saw the list from the AT motherboard's BIOS.

Could this be an explanation why during high level formatting it shows about 612 cylinders to be formatted and always fails at cylinder 302

You are partitioning and high-level formatting on an AT.
With the OMTI 5520A in your AT, you will have set the hard drive type number in CMOS SETUP to 0 (i.e. no AT-class controller).
Therefore, the source of the cylinder count of 612 in FDISK must be the OMTI 5520A controller, specifically the 5520A's drive-type jumper setting.

FORMAT.EXE failing at cylinder 302 is presumably because your Rodime drive only has about 300 usable cylinders. I looked for information on the Rodime RO250 drive, but could not find anything.

 

[modem7]

I'm afraid for a test with the XT I would have to get my floppy drive controller fixed first. This is one of the reasons why I'm trying to get the fixed disk working (Is there a good thread somewhere with some help about?)

For the faulty floppy drive controller, create a new thread about that.

 

[modem7]

This is the content of the EPROM on the OMTI controller.

I have added that to the collection at [here]. I could not find an obvious version number in the content. For identification purposes, what is printed on the ROM's sticker ?

@modem7, do you think the sstor output on the AT is reliable in order to adapt the BIOS of the controller?

As I wrote before, you may not have seen the 5520A's drive list.

But looking at the ROM content that you posted, I see what appears to be a block of 16 entries. For each entry (16 bytes per entry), I do not know what all of the bytes are (OMTI does), but the early ones are cylinder and head counts. I will modify those 16 entries to {300 cylinders, 4 heads} then send you the modified content via PM. If that doesn't work then, the path of drive overlay may be the way to go.

 

[Dallas_Green]

Hello

Because you ran that on an AT-class computer, SpeedStor might have showed you the drive table in the motherboard's BIOS (because that is where it resides in an AT-class computer).
In the OMTI 5520A's BIOS ROM, there are only 16 drive entries.
If you saw more than 16, then you probably saw the list from the AT motherboard's BIOS.

Yes, seems that way. It shows more then 42 entries. Probably it comes from the motherboards BIOS since it sstor mentions something from AT disks.

I looked for information on the Rodime RO250 drive, but could not find anything.

What kind of information were you looking for? Does this help? I did write something wrong before. Its a RO352 device. The original one from a Compaq Portable Plus.

I have added that to the collection at [here]. I could not find an obvious version number in the content. For identification purposes, what is printed on the ROM's sticker ?

Well on the ROM it self there is just printed "SYNC. 5-A000" although I'm not sure about the last 4 digits. It's no that readable anymore.
If I look at this documentation here and the listed BIOS release info then a number from another IC on the card looks more similar to this.

From website: 1002450, 1002452 or 1002571, ...
Marked on the controller: 1102564-C

 

[Dallas_Green]

Thanks for your help with the ROM content.

I will modify those 16 entries to {300 cylinders, 4 heads}

Does this sector/track value matter for the configuration? Cyls=306 Heads=4 Sec=32

 

[modem7]

What kind of information were you looking for? Does this help? I did write something wrong before. Its a RO352 device. The original one from a Compaq Portable Plus.

Sometimes I double check provided information. Cylinder count and head count was what I wanted to double check on.

Does this sector/track value matter for the configuration? Cyls=306 Heads=4 Sec=32

This is part of the problem. There is no international standard for the format of the drive table in the BIOS of an XT-class MFM/RLL hard disk controller. Each maker did what they wanted.

The table in your controller's BIOS is most likely what is shown below in the diagram. The first two bytes of each entry are sure to be the cylinder count. The third byte will be the head count. The fourth and fifth bytes are probably the WPC cylinder (unimportant these days). What are the others? What impact do they have?

As for sectors/track, the figure that your controller uses may be fixed at something (used for all entries in the table).

What I am confident about in your controller's BIOS is as follows. Note that the twelfth entry is for {Cyls=306 Heads=4}. So there will be a W1-W4 jumper configuration that selects that. Maybe it is {W1: open}{W2: closed}{W3: open}{W4: open}, but sometimes the table runs backwards, so possibly {W1: closed}{W2: open}{W3: closed}{W4: closed} instead.

It could be that your controller was jumpered properly all this time, and your problems all stem from doing things in an AT-class computer.

 

[Dallas_Green]

@modem7,

Thanks for this hint with the parameter table. I tried the first jumper setting you proposed {W1: open}{W2: closed}{W3: open}{W4: open} and it worked directly at the beginning. It could read the DOS I put there via the AT the other day.
So it seems that this mystery with the jumper setting is discovered know, alltough I couldn't con sstor yet. Its just about having the parameter - jumper table to the bios version on the controller. Thank you very much for having this analyzed.

Unfortunately I cannot do much with the system know since the enter/return key on the keyboard doesn't work. Actually there are just a few keys which work. So I have to wait know until the packege with the new foam/foils pieces from Texelec arrives.
But I really can see a big progress here with the Compaq - step by step. And this is thanks to you =)