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MDM5 and CFORM with MFM drives


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#1 BeeryMiller OFFLINE  

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Posted Tue Sep 11, 2018 9:11 AM

Got a question regarding hard disk formatting.

 

Has anyone ever formatted a 1024 cylinder image (or more) with either MDM5 or CFORM on a TI-99/4A or Geneve 9640?

 

I tried an 8 head, 1024 cylinder, 32 sector/track with CFORM and while it reported it wrote the bitmap correctly, the bitmap was not there on the 64 MB image.  Thinking something may be unique about CFORM I do not understand yet.  I will try MDM5 tonight, time permitting.

 

Also, has anyone ever used either CFORM or MDM5 to format a MFM drive with more than 1024 cylinders?

 

MDM5 will allow you to enter more than 8 heads, but as designed, the HFDC without modification will only allow 8 heads.  Barry Boone has an article in Micropendium that allows you to add another line so one can use 16 heads.  Myself, no interest at present of this modification.

 

So, since MDM5 can allow more than 8 heads, is anyone aware of an issue with something greater than 1024 cylinders would be an issue?  Did anyone ever have a MFM drive with 1024 or more cylinders where this was ever tested?

 

Beery

 



#2 InsaneMultitasker OFFLINE  

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Posted Tue Sep 11, 2018 10:43 AM

If I recall correctly, the 9234 chip addresses at most 2048 cylinders, though I don't recall ever formatting a drive with more than 1023.



#3 BeeryMiller OFFLINE  

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Posted Tue Sep 11, 2018 11:30 AM

If I recall correctly, the 9234 chip addresses at most 2048 cylinders, though I don't recall ever formatting a drive with more than 1023.

 

I was debating whether to drop the cylinder count by one to 1023.  I may try doing that on the Geneve this evening as well.

 

Beery



#4 RickyDean OFFLINE  

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Posted Tue Sep 11, 2018 12:18 PM

 

I was debating whether to drop the cylinder count by one to 1023.  I may try doing that on the Geneve this evening as well.

 

Beery

Well if you have a sector 0 and a track zero, there is probably a cylinder 0 (corresponding to a track zero) this would account for only going to 1023, still 1024 cylinders.



#5 BeeryMiller OFFLINE  

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Posted Tue Sep 11, 2018 2:38 PM

Yeah, that was on my mind as well.

 

I've had several discussions with Oleksandr regarding heads on the same similar subject as his displays on the monitor attached to the DREM show formatting heads 0 through 7 when I enter 8.

 

We had a discussion whether when I entered 8 heads if it was heads 0 through 8, or 1 through 8 as far as count.

 

What I did not understand was why many of the early MFM drives had odd numbered heads.  In fact, I have not seen any with even numbered heads.  I do not know if there is something in the design of the platters that prohibited access to one side of one of the platters, or ????

 

Beery



#6 BeeryMiller OFFLINE  

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Posted Wed Sep 12, 2018 5:08 AM

Apparently CFORM, or the version I have, has some issues with formatting some 1024 and 2048 cylinder hard drives.

 

MDM5 last night formatted a 8 head by 1024 cylinder by 32 sector per cylinder image (64 MB) and an 8 head by 2048 by 32 sector per cylinder image (128 MB) without issue with the DREM emulator.  I've now got over 500,000 sectors free on the 128 MB image.

 

Beery



#7 RickyDean OFFLINE  

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Posted Wed Sep 12, 2018 5:44 AM

Apparently CFORM, or the version I have, has some issues with formatting some 1024 and 2048 cylinder hard drives.

 

MDM5 last night formatted a 8 head by 1024 cylinder by 32 sector per cylinder image (64 MB) and an 8 head by 2048 by 32 sector per cylinder image (128 MB) without issue with the DREM emulator.  I've now got over 500,000 sectors free on the 128 MB image.

 

Beery

That's so cool, now when I can afford them, I want to buy three, one for each of my HFDC's and one to use on my Personality Card!!



#8 BeeryMiller OFFLINE  

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Posted Wed Sep 12, 2018 7:10 AM

I have no idea if there is any development needed with the personality card as I know nothing about the chipset.

 

The good thing is Oleksandr has been EXTREMELY supportive to make it work with the 9234 chipset on the HFDC and one could not ask for any more timely response.  As fast as I could give him log files and comments on what I was seeing, he was adding the extra support.

 

If it is using the Western Digitial chipset, it is likely just a matter of using the right config commands in the CFG file for the emulated image.

 

Beery






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