hcj@lzaz.ATT.COM (HC Johnson) (01/05/88)
There have been many posting with regard to strange ST behavior when using the SH204 disk. After discussing this with Chris at BMS I learned the following: 1. SH204 seems to report 8 drives per controller. I saw this with the BMS driver on my SH204. Also Magic -Sac describes this. 2. That isn't the problem. 3. SH204 CANNOT report ANY ERROR to the computer. So why doesn't everyone die on a disk error? The Adaptec interface does the retries, and if successful, all is well. What happens if the sector is BAD? You read in junk, fail to get the error message, and see strange things. BTW, hdx CANNOT mark as bad the blocks in the root directory or the SAMS. This creates really strange problems when a block changes, as when adding files and suddenly 5 megabytes dissapper. I solved my problems 2 ways. 1. I changed hdx to accept a list of bad blocks and let Adaptec remove them permanently. 2. I now use a BMS controller. Highly recommended. Any one want to buy a slightly used SH204?
jwt@atari.UUCP (Jim Tittsler) (01/06/88)
In article <46@lzaz.ATT.COM>, hcj@lzaz.ATT.COM (HC Johnson) writes: > [...] > 3. SH204 CANNOT report ANY ERROR to the computer. > > So why doesn't everyone die on a disk error? The Adaptec interface > does the retries, and if successful, all is well. What happens > if the sector is BAD? You read in junk, fail to get the error message, > and see strange things. That is definitely NOT true. The SH204 and SH205 do indeed return with an error flagged when one occurs. Jim Tittsler, Atari Corporation
jack@cwi.nl (Jack Jansen) (01/06/88)
In article <930@atari.UUCP> jwt@atari.UUCP (Jim Tittsler) writes: > >That is definitely NOT true. The SH204 and SH205 do indeed return with >an error flagged when one occurs. > >Jim Tittsler, Atari Corporation If this is true, there's some pretty lousy software inside the ST. Some time ago, a friend of mine connected a 40Mb drive instead of the 20Mb inside the 204, and, in the process of finding out how big it was, he noted that he could format 40Mb, 60Mb, 100Mb, etc etc etc. So, we blamed the drive and repeated the process with the standard one. Same thing. You can format a SH204 as 4 10Mb partitions. No problem. You can even write files onto the third and fourth partitions. No errors. Of course, reading the files again proved to be rather disappointing. Since that time, I've started to be *very* careful with my SH204...... -- Jack Jansen, jack@cwi.nl (or jack@mcvax.uucp) The shell is my oyster.
apratt@atari.UUCP (Allan Pratt) (01/07/88)
in article <46@lzaz.ATT.COM>, hcj@lzaz.ATT.COM (HC Johnson) says: > > After discussing this with Chris at BMS I learned the following: > 3. SH204 CANNOT report ANY ERROR to the computer. That's just not true. I don't know why he thought so. CRC errors, seek errors, sector-not-found errors all can be presented to the CPU as error conditions after a seek, read, or write operation. > BTW, hdx CANNOT mark as bad the blocks in the root directory or the SAMS. I assume you mean FATs, not SAMS... I don't know where your terminology comes from. But it's not HDX's fault, and certainly not the controller's. That's the fault of MS-DOS, of which GEMDOS is an approximate clone. We never claimed we could do bad-block forwarding, and there's no other way to mark blocks which are bad in the part of the disk that holds the bad-block information. It *is* HDX's fault that it doesn't record bad blocks very well. For instance, it doesn't remember bad blocks when you repartition or reformat the disk. We at Atari are building new hard disk tools which will record bad blocks better, and keep track of them across repartitioning and reformatting. Furthermore, it will refuse to put a partition header (the boot sector, FATs, and root directory) in a place with a bad block. HDX should have done this, but didn't. ============================================ Opinions expressed above do not necessarily -- Allan Pratt, Atari Corp. reflect those of Atari Corp. or anyone else. ...ames!atari!apratt