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Bringing up hard disk with unknown parameters

sdltrs doesn't appear to like the hard disk data that I extracted with the MFM emulator. Maybe it needs some sort of structured data with a header, rather than a raw sector data dump?
 
Aha! I figured out why the number of cylinders displayed by DIR is half the number I expected. There is a logical vs. physical translation going on. From the RSHARD manual, describing entries in the Drive Control Table (DCT):

This bit, termed the DBLBIT, will be SET if you requested more than 203 cylinders for a single logical drive. In this case, a logical cylinder is composed of two physical cylinders.
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This appears to be consistent with what I'm seeing in the DCT, which I'm studying with DEBUG while trying to figure out how to apply the model 4P boot patch as described at http://www.trs-80.com/trs80-zaps-dos.htm#m4phardboot

Incidentally, the instructions there state that the DCT can be found at 0x0370, but what I was seeing there didn't make sense. I looked in the LS-DOS 6.3.1H source code and found that it appears to actually be at 0x0470.

Don't ask me about any of this stuff in a week, because I'll have forgotten all of the details by then!

Edited to add: I'm not really positive about the 0x0470 address, either. I'm comparing what I see there to the DCT details in the RSHARD manual, and it doesn't seem consistent to me yet.
 
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I think I've found newer and better patching instructions HERE in file HDBT2/TXT on the "Hard Disk Driver & Utilities" disk image, which I'm looking at in sdltrs. I'm still confused by one thing, though. The instructions direct me to insert the number of sectors per granule in a particular spot in one of the patch files, but they don't describe how to determine that number. Is this something that would be obvious to an experienced LS-DOS user?
 
NF6X said:
I think I've found newer and better patching instructions HERE in file HDBT2/TXT on the "Hard Disk Driver & Utilities" disk image, which I'm looking at in sdltrs. I'm still confused by one thing, though. The instructions direct me to insert the number of sectors per granule in a particular spot in one of the patch files, but they don't describe how to determine that number. Is this something that would be obvious to an experienced LS-DOS user?
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G'day Mark,
RSHARD6 will change the sector/gran value depending on the the size of the partition.
For a 203 cyl partition try 4 sectors/gran or for 406 cyl, 8 sectors/gran should do the job.
According to my notes which may or may not be correct.

203 cyl - VV = 00 00 00, WW = 20, XX = 20, YY = 04, ZZZZ = 0C 90 00 CA IF E3

406 cyl - VV = CD F7 43, WW = 20, XX = 40, YY = 08, ZZZZ = 0C B0 00 CA IF 67

cheers
Gazza
 
I made an educated that the file size shown for a minimum length file in DIR is probably one granule. Everything on the hard drive appears to have sizes divisible by 2.00K, so I think I have 8 sectors per granule.

This 15M hard drive has 306 cylinders, 6 heads and 32 sectors per physical cylinder. Luckily it's already partitioned with one partition per head, so it meets the requirement that drive 0 must be entirely under head 1.

Using the HDBT2/TXT nomenclature, I think that for my particular hard drive:

Code: 
vv = CD F7 43
ww = 20
xx = 40
yy = 08
zz = 0C B0 00 98 1F 67

I've typed in the /FIX files by hand in TED (so much character built!), and I'll try crashing things shortly. ;)
 
Cool! I've never seen this working before. The Tandy hard drive looks good sitting on top of the 4p. The proportions kind of match.
 
Minor update: I've tried out the emulation mode of this cool card with it attached to the controller card in place of the TM503 drive, and that works, too.
 
Have you tried the MFM emulator with any other systems yet? Mine should be arriving tomorrow. I already have a BBB. Haven't looked into what it takes to set up the software on it yet.
 
gslick said:
Have you tried the MFM emulator with any other systems yet? Mine should be arriving tomorrow. I already have a BBB. Haven't looked into what it takes to set up the software on it yet.
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No, just this one. I made an initial attempt to use it to image a Color Computer hard drive setup that I got from eBay, but found out that the drive doesn't work. The drive's busy LED pattern indicates a problem with the track zero sensor, so maybe I can repair it?

I don't think I have any other MFM hard drive systems at this time.

Edited to add: If you ordered the emulator along with a BBB, then the software will already be installed on it.
 
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