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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: amigafeeling on June 01, 2015, 03:48:03 PM
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Hi,
I'm attempting to install a HD Seagate ST-238R on my Commodore A2090a : it's a MFM 30 Mo formatted hard disk.
4 Heads and 615 cylinders indicated on the net.
With "Prep RES0:", i prepared it : 4 Heads, 615 Cylinders and 17 Blocks per track (the maximum authorized by the software).
But, once formatted, partition makes only 20 Mo, not 30 Mo.
It's the fault of the 17 Blocks per track max i think.
Is there a solution ? (I tried with 5 heads, after 800 cylinders, but it doen't work).
Thanks for your help.
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IMHO you're making it really hard for yourself by using an A2090A. Sure you don't want to upgrade to even a slightly more modern controller, like an A2091 or GVP, and use HDToolbox? Good luck!
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i own others controllers ... but it's a challenge for me !
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ST-238R is not MFM. It's RLL.
Won't work on a MFM controller.
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No it's working : formatting a 20 Mo partition on my A2090 is a success.
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No it's working : formatting a 20 Mo partition on my A2090 is a success.
The '80s called. They want their hard drive controller back. :lol:
(http://s3.amazonaws.com/rapgenius/1380048783_Zach-Morris-80s-Phone.jpg)
Just kidding, this sounds like an awesome challenge if you're just doing it for fun!
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Mark Paul Gosselar !!
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ST-238R is not MFM. It's RLL.
Won't work on a MFM controller.
mfm/rll are basically the same scheme and i quote :
"Modified Frequency Modulation, commonly MFM, is a run-length limited (RLL) coding scheme used to encode the actual data-bits on most floppy disks."
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I stand corrected.
Guess with the RLL you get more capacity. Formatting it MFM drops the 38MB drive back down to 20MB.
Guess the ST-238R was just a ST-225 with RLL encoding.
Hmmm, learned something today that I should've known all along!
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Curtis,
Do you have a good link to give me about MFM / RLL encoding ?
I'm interested.
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The Spec for the Seagate ST238R is 5.25" HH RLL Hard Disk with 32MB Capacity (RLL Formatted) Cyl 615 Heads 4 Access Time 65mS SPT 26. The Maximum MFM Capacity will be 21 MB.
I have a huge Chart for ST-506, ESDI and SCSI Drives I've Installed HDD's since 1986.
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RLL encoding added to plain MFM disks extra capacity of 50%; this was in the PC realm and not the Amiga. Just Praise The Lord that it still works at all -- or donate it to a tech refurb company and see if it is really an Apple I instead.
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Well, there's always good ole wikipedia:
http://en.wikipedia.org/wiki/Modified_Frequency_Modulation There's a link that explains RLL is Excruciating detail near the top of the MFM article.
An interesting thread on google groups has a pretty discussion of the differences also:
https://groups.google.com/forum/#!topic/comp.sys.ibm.pc.hardware/pc09c_yHWr8
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Lord, that is a boring read.
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Hi,
I'm attempting to install a HD Seagate ST-238R on my Commodore A2090a : it's a MFM 30 Mo formatted hard disk.
4 Heads and 615 cylinders indicated on the net.
With "Prep RES0:", i prepared it : 4 Heads, 615 Cylinders and 17 Blocks per track (the maximum authorized by the software).
But, once formatted, partition makes only 20 Mo, not 30 Mo.
It's the fault of the 17 Blocks per track max i think.
Is there a solution ? (I tried with 5 heads, after 800 cylinders, but it doen't work).
Thanks for your help.
Where in the hello operator did you find a MFM/RLL board for an Amiga, I had one of the first HD boards out for the A1000 which was a Supra SCSI, maybe I just didn't notice that they had a board like that since I had the Supra drive, lets see last time I used a MFM / RLL drive you had to use a debug g500 or 800 command to set up the timing marks which took about 4 hours, then you had to format the drive which took another 2 to 4 hours. Man am I happy those days are gone. Went up in the attic after reading this and found my first PC computer, a 286 with an MFM controller board, modem, sound blaster, and a star vga card. Still have them, but I think my wife threw away the case when we moved. When I get time will try to see if it still works, In the mean time, just brought out an old ASUS card to set up my ADS DVD Xpress equipment, and got it working, then I took my friends old VCR tape and put it through the ADS Xpress and transferred it over to a mpeg file so I can write it to a DVD, Talk about a tape from HELLO Operator, this tape was in storage so long that I had to FF it and then Rewind it a hundred times to get it to play right, the tape was so tight from sitting that when I tried to play it at first it would not run, then after doing the ff and rewind it ran but it was choppy and the video was bouncing up and down, after it finally loosened up, where I could play it and record it, talk about magnetic fuzz, and distortion, nothing you can do about that, used my video stabilizer and clarifier, but the magnetic leakage and distortion was still really bad, but he should be happy at least now he can watch his 8 year old son play in the championship season with Holy Cross school, his son now works for IBM in Chicago, been working there 5 years already after graduating college, tells you how old this tape is.
You know one of my problems is that I never throw anything away, especially computer wise, I am an electronic parts hoarder, when a part goes bad, like a HD, I tear it apart so that I can use the case for an electronic project. the magnets (lots of fun) and the HD plates hang on the wall like donut mirrors. I just tore apart a Sony 60" rear projection TV, Going to use the back of the case for the roof on an outdoor shed for gardening equipment, the cooling fans for my computers, the wire (always useful) and looking at the projection part to see what I could do with that, it is the bad part, the LCD's went bad. Just tore apart a Memorex VCR. kept the case for a project box, the wire, and the ckt boards. Am I nuts or what?
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Told ya so!
Lord, that is a boring read.
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Uh, Smerf, all A2090 cards support MFM drives.
The systems they were included in invariably contained MFM drives.
Frankly I don't miss these older hard drive even though my first hard drive was a 40mb Seagate (ST251 I think).
IDE drives, once they were introduced, were SO much easier to set up.
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You're right Curtis.
You can read that :
http://redhill.net.au/d/10.php
Thanks for your help.