Maxtor XT-2190 MFM Help

[aplmak]

Ok.. so I’ve tried and tried on my Xenix box to format this drive with the specs from

Hard Drive: MAXTOR: XT-2190 155MB 5.25"/FH MFM ST506

Manufacturer: MAXTOR model: XT-2190 capacity: 155MB, physical size: 5.25in/FH , interface: MFM ST506 , hard driver specs and jumper settings, layout and features

stason.org

Well it doesn’t like to go past 16 sectors I’m pretty sure. The specs say 17. Now if I configure it with specs of let’s say a Micropolis 80MB drive it will work fine! So if I put 1024 cylinders 8 heads 16 sectors… it’s fine, albeit is 80MB. I’m not sure if this machine allows up to 190MB but it does recognize when I install Xenix that it is a 190MB drive.. it’s just it gives all sorts of errors and abandons the install. One of my machines did come with an XT-2190 in it and somehow they got it to configure with that drive info. I’m not sure how they did it. Typically these machines go up to 80MB MFM hard disks.

According to specs Maxtor XT-2190 it’s 1224 cylinders 15 heads and 17 sectors.

Any ideas on what I could try?

Thanks!

 

[aplmak]

This will work.. see attached..

 

[aplmak]

This will not work… see attached..

 

[aplmak]

I’m having a feeling it’s a limitation on the machine… but could I possibly format it as a 190mb on a different Unix type machine that can handle it and then use it?? (And flag all bad spots on the drive of course..)

 

[Makefile]

What controller card are you using? I believe one of the pins in the control cable was repurposed as "head select 3" with some previous meaning, so the card may have a "drive has 8 heads or less vs. drive has more than 8 heads" jumper.

 

[aplmak]

It’s a Western Digital WD2010 chip on proprietary controller card.

Hopefully that helps.. it’s a regular WD2010 IC

 

[aplmak]

It’s a Western Digital WD2010 chip on proprietary controller card.

There are some jumpers on the controller board but I’ll have to try to find some docs on that controller board..

 

[djg]

Hopefully that helps.. it’s a regular WD2010 IC

If you look at the datasheet the field for head is only 3 bits. Unless the card did something special its only going to support 8 heads. Their are some machines with this chip that put the 4th head bit in a different header field to get around it. The actual head select signals are generated external to the chip.

Pg 3-119. https://www.digchip.com/datasheets/parts/datasheet/000/WD2010-05-pdf.php

 

[aplmak]

Out of curiosity any way one could throw a different WD that could read more than 8 heads? Just a crazy question or would some other tweaks needed to be performed?

 

[aplmak]

And oddly as it sounds.. someone before me who owned this threw an XT-2190 in it and it recognizes from what I see all the heads.. I think.. I’ve pretty much filled it up with data.. unless they tweaked that controller board?? I’ll have to take a look. I have a lot of extra controller boards for these machines. Some have WD2010B-PL’s but most have WD2010-AL

 

[aplmak]

And one last crazy question. Could it just be used as is configured with 8 heads and work normally albeit not reaching its full potential of 190mb? Thanks by the way for everyone’s feedback

 

[vwestlife]

According to specs Maxtor XT-2190 it’s 1224 cylinders 15 heads and 17 sectors.

Those specs are for 256 bytes per sector. DOS (and probably XENIX too?) uses 512-byte sectors.

And 190 MB is the unformatted capacity -- in other words, pure fantasy. The actual formatted capacity is 155 MB (decimal) or 148 MB (binary).

 

[aplmak]

Those specs are for 256 bytes per sector. DOS (and probably XENIX too?) uses 512-byte sectors.

And 190 MB is the unformatted capacity -- in other words, pure fantasy. The actual formatted capacity is 155 MB (decimal) or 148 MB (binary).

Gotcha.. any idea what values I should try instead to get the maximum space? Cylinders, Heads, Sectors, Sector Size? I’m open to suggestions… can someone throw out some tweaks I can give it a shot.

Btw this is just tinkering around.. I use David Gessweins MFM SSD emulator mostly but since I had these lying around I thought I’d play with them.

 

[Chuck(G)]

I've been trying to follow this one and am scratching my head.
Almost all 5.25" hard drives using MFM encoding put 17 sectors of 512 bytes on a track. The 2190 allows for 33 sectors of 256 bytes also.
The fly in the ointment is the 1224 cylinders (other than the 8 head limit). Most HD BIOSes of the time allow for 1024 cylinders. (See Int13H docs on that). At least one AT-style controller allowed for the full 1224 by borrowing some bits from the "head" register in the BIOS call. Before that, I wrote a loadable driver that showed the extra 200 cylinders as an extra drive.

 

[eswan]

The earlier ST412 standard had an 8 head limit. ST506 allowed 16 heads by changing the write-precomp line into another head select. I think the earlier WD1010 only allowed 1024 cylinders, while the 2010 allowed 2048. But you are also limited by what the software will support. On the Tandy 6000 with Xenix, it needed patches to go beyond 1024 cylinders.
In any case, I would expect it to work fine as a 1024 cyl 8 head 17 sector drive. Might have to tape over the head select/write precomp pin (2?) on the control cable.

 

[aplmak]

Understood.. what is so wacky is I have another XT-2190 with the specs in this photo.. and it works pretty much 99% of the time. I can actually fill up all the data basically.. almost every block. It shows close to 190mb. Even an image of it on the MFM emulator board. I have no idea how the person before me was able to set this configuration.. perhaps on another machine and then moved it?

I’m open to tinkering and trying stuff.. the problem is the Xenix 3.2 installer will only recognize certain sizes.. 190 is seen and allowed to install but I get block errors. If I change it to let’s say 150 it won’t work. The manual says up to 80 MB. But the installer will take 190.

Again anyone wanna throw out some numbers for me to give it a shot and see if it works? I’m totally willing to try some tests with some numbers and see how it goes..

 

[djg]

Out of curiosity any way one could throw a different WD that could read more than 8 heads?

This would depend on if your BIOS and Xenix supported the newer board. No reason it couldn't be done but don't know the details. Never used Xenix.

And oddly as it sounds.. someone before me who owned this threw an XT-2190 in it and it recognizes from what I see all the heads..

You think they were using the same controller you are using? Would require knowledge of your particular machine to understand this.

Gotcha.. any idea what values I should try instead to get the maximum space? Cylinders, Heads, Sectors, Sector Size?

You can give 1224, 8, 16, 512 a try. Did you try 1024, 15, 16, 512? If not try that also. Think you said that 1024, 8, 17, 512 didn't work but not sure. Might get slightly more space with 1024 byte sectors and 9 sectors though good change that won't work. You also said Xenix only likes certain sizes so that may restrict what you can do.

Almost all 5.25" hard drives using MFM encoding put 17 sectors of 512 bytes on a track.

Looking through my drive formats DEC professional is probably most common machine that used 16 sectors. NorthStar_Advantage, Soviet iSBC 214 clone SM-1810, and NIXDORF_8870 are the others I find.
Unusual for PC type machine. That drive should have good control of RPM. If its spinning too fast that would prevent 17 sectors. Emulator can check the RPM. Could try the emulator or another drive and see if it will format 17 sector on that controller.

Assuming drive RPM is correct the sectors per track is set by the controller gaps sizes it uses so the drive may format fine on one controller at 17 sectors per track but if the controller your trying has large gaps between sectors etc intended for 16 sectors per track you will only be able to format 16 sector per track.

And one last crazy question. Could it just be used as is configured with 8 heads and work normally albeit not reaching its full potential of 190mb?

Yes.

The earlier ST412 standard had an 8 head limit. ST506 allowed 16 heads by changing the write-precomp line into another head select.

ST506 was Seagate's the first drive. ST412 was the second. ST412 added buffered seeks over ST506 which all later drives used so would have been more accurate to refer to drives as ST412 standard but not normally done. More than 8 heads came much later than either of those drives. As vendors modified the interface later people still referred to it as ST506.

 

[aplmak]

You can give 1224, 8, 16, 512 a try. Did you try 1024, 15, 16, 512? If not try that also. Think you said that 1024, 8, 17, 512 didn't work but not sure. Might get slightly more space with 1024 byte sectors and 9 sectors though good change that won't work. You also said Xenix only likes certain sizes so that may restrict what you can do.

So when I give these a shot what drive should I set it at? 190MB? It asks for the size in megabytes before you complete the drive configuration, but it won't do any auto calculation or anything, you must specify. And because of all the head changes and whatnot I am not sure what parameters designate effect the size. (My apologies in advance if I sound completely stupid here.)

Thank you for your help.. I will give it a whirl

This is one of those strange machines as it is an Altos 886 running their own licensed version of Xenix 3.2 from Microsoft. The machine has a main motherboard and then a controller board that has the WD2010 chip and other chips for the floppy drive and tape drive. It's a sort of combo board. I am not exactly sure where a BIOS would be on this thing. I've never heard of a BIOS on these machines.. I do not believe they have them. I've been playing with Altos machines going back to 1990's. I dabble here and there over the years on them.

 

[aplmak]

This is what an Altos 886 type machine has for a controller "card" more a board which is a combo floppy, hard drive, and tape controller board.

 

[eswan]

ST506 was Seagate's the first drive. ST412 was the second.

Arrrgh... I _always_ get those backwards.

So when I give these a shot what drive should I set it at? 190MB? It asks for the size in megabytes before you complete the drive configuration, but it won't do any auto calculation or anything, you must specify.

I wonder if it actually uses that for anything. Those screenshots trigger memories of setting up (BSD?) disklabels once upon a time, and If I remember correctly, they're more for documenting the configuration. Same with the "Maker....Maxtor " field. I'd try 1024, 8, 17 first. That would prove the drive is working. If that worked try 1024, 9, 17. That would show controller/software support for heads > 8.
1024x8x17/2 = 69632 Kbytes, 70 MByte. (divide by 2 because 512 bytes per sector is 1/2 Kbyte)

This is one of those strange machines as it is an Altos 886

I think I've still got an Altos 2086 kicking around, not sure what size drive. I'll take a look at how it's configured.