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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

1276.0. "SH205 FAT corruption problem" by KERNEL::IMBIERSKI (The sound of electric wood) Mon Apr 06 1992 10:00

    This is going to be a bit long, but if any ST file system gurus could
    have a read and give me some advice I'd be very grateful!

    I'm trying to use an SH205 hard disk with an old STFM running 1.0 TOS
    (in ROM) and (I think) 1.2 GEMDOS, and 3.01 of AHDI. The disk was
    second hand and had software already on it which loaded and ran
    perfectly. However, when I tried to save my own files to the disk it
    rapidly corrupted to such a state that I had to reformat. I put more
    files on the disk after reformatting and these too became corrupt,
    including directories.

    At this point I decided some in-depth troubleshooting was required so I
    reformatted the disk, copied ONE file to it and loaded up KNIFE-ST from
    floppy. What I found was that the list of clusters for the one file in
    the FAT ended with ZERO for the last cluster, instead of -1 which (I
    thought) should designate the last cluster in the chain. The data
    content of the file itself was all there on disk, with the EOF marker
    in the cluster marked as 0 in the FAT.

    Now a forward pointer of 0 in the FAT means "this cluster is unused" so
    clearly, when I copied other files to the disk, this cluster got
    re-used by another file, and my first file was corrupt.

    Just to try and make this clear, my expected layout of a FAT chain
    would be something like:

    Cluster 1, Cluster 2, Cluster 3, Cluster 4, Last Cluster 
    0002,      0003,      0004,      0005,      FFFF 

    what I see on the SH205 is:

    Cluster 1, Cluster 2, Cluster 3, Cluster 4, Last Cluster 
    0002,      0003,      0004,      0005,      0000 

    Note the hard disk uses 16 bit fat entries. My floppies work fine (they
    have 12 bit FAT entries).

    So, the questions that come to mind are:

    1). What part of the operating system is responsible for building the
    FAT chain. (TOS?).
    
    2) If I need a TOS upgrade, is it still possible to get roms for, say,
    1.4?? If so what is the typical cost?
    
    3) If I patch into the BPB routine and make it report 12 bit FAT
    entries instead of 16, will this cause other problems??
    
    4) Would the version of AHDI have any effect??

    Hope someone can help!!

    Tony I

    
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1276.1KERNEL::IMBIERSKIThe sound of electric woodTue Apr 07 1992 09:1811
    Well, I'll answer my own note in case anyone else is interested!
    
    I've spoken to a UK company, Ladbroke computing, who agreed that a TOS
    upgrade would be a good thing to try. However other "technical support"
    people have suggested it will either be a DMA or a controller problem. 
    
    As I see it, though, the DMA and the controller do not know anything
    about the FAT. Surely this must be handled within TOS? Can anyone
    comment on this before I spend my money??
    
    Tony I
1276.2try another driverUFHIS::BFALKENSTEINTue Apr 07 1992 13:2016
    
    I'd go for a new TOS version, though I would also try out another
    Harddisk-driver first. These are floppy-based and so easier to get...
    I had a similar problem when I used CBHDI (another driver) and formatted 
    one partition for use with ATonce and MS-DOS. This didn't work! 
    After installing MS-DOS on the DOS-formatted partition I just could 
    boot DOS once and then never again because all the files in the 
    DOS-directory were corrupted after the first boot-up. Formatting the 
    drive with the Atari-driver (AHDI) did the job. When I looked at the 
    boot- and rootsectors I found 3 partitions with the ID Atari with 
    start- and ending sectors that were ok and another three partitions
    with negative startsectors and the ID "Scheibenkleister" from CBHDI.
    So, although I formatted the drive with HDX there still was a mess in
    the boot- and rootsectors from CBHDI...
    
    Bernd                
1276.3KERNEL::IMBIERSKIThe sound of electric woodTue Apr 07 1992 13:5612
    thanks for the reply, Bernd.
    
    what other HD drivers are there? I'm a bit new to hard drives. I'm
    using Atari's AHDI which came with the drive, but I have seen mention
    of a SUPRA driver in this conference. Are these other drivers usable on
    an atari disk or are they specific to particular hardware??
    
    Are there any drivers I can pick up off the network??
          
    cheers,
    
    Tony I
1276.4CMOTEC::HARRISONTue Apr 07 1992 14:228

Hi, 
	I've got the ICD set of programs, including hard disk driver,
I don't know if they would be of use to you ?


Brynn.
1276.5updateKERNEL::IMBIERSKIThe sound of electric woodWed Apr 08 1992 12:2014
    well.....
    
    the lastest update on this is that I tried the hard disk on a friend's
    ST and it works PERFECTLY. His machine is even older than mine and has
    the same ancient TOS version.
          
    So, even though I can't understand how it could possibly happen, this
    must be down to a hardware problem in my ST. Now the only obvious
    culprit must be the DMA chip, or is there anything else I should
    check??
    
    Confused!
    
    Tony I
1276.6DMA chip is a good guessPRNSYS::LOMICKAJJeffrey A. LomickaWed Apr 08 1992 20:489
The DMA chip is a good first guess, and is easily replaced
speculatively.  I have fixed many weird disk problems by replacing the
DMA chip.

Also, if you have never used a hard drive before, it may be a
simple as spraying some contact cleaner on the DMA port, as it may have
corroded after years of not being used.


1276.7fixed!KERNEL::IMBIERSKIThe sound of electric woodFri Apr 10 1992 09:1115
    I've fixed my Hard Disk problem....
    
    I bought another ST!
    
    I got so fed up with this problem I didn't want to spend any more money
    without guaranteeing a fix. STFM's are so cheap on the second hand
    market I decided to just buy another and have done with it (After
    trying out my Hard Disk with it, of course). The "new" machine cost
    about twice what most repair companies quoted my to fix my old one.
    
    Thanks to everyone who helped me with this, especially Brynn!
    
    Cheers, 
    
    Tony I