#scsi problem
13 messages in this thread
I left a message ( 96402 ) that was addressed to AL, I meant ALL. Is it
possible to change it?? Do you know of anybody who has a 2000 configured the
way I described in msg 96402 that is having problems with their drive or having
it work great ???? Thanks in advance.
Paul Montgomery
Paul, I'll change it for you. Marlene
Marlene, Thank you, I havent gotten any replies on the problem, and it wont go
away. Any Ideas???? Paul Montgomery
Paul, I don't remember what problem you were having – how about re-stating it
and we'll see if anyone has a solution. Marlene
Marlene,
Larry and Bob Rakosky have been doing there best to show me what I am
doing wrong, but I still have trouble accessing my scsi drive when two screens
are showing. The scsi gives me a read/write error most every time it is
accessed with 2 screens showing, but not one. I put slow mem last in my
startup-sequence before anything else, I have the latest driver. Any other
suggestions? My environment is an A2000, a 2090, 3 meg ( one asdg 2mg board-
recent addition, no difference ), 1 miniscribe 8425 ( a 20 meg st506 type drive
) as the system disk, 1 ST251N ( a 40 meg scsi drive ), two 3.5 floppies ( one
external ) and thats all. question: to any one with the ST251N how many cyl
did you say you had at prep time? Did you say 820 or 807 or what. I said 820
first prep and then at format time it wasnt able to format past 807. I
re-preped with the cyls at 807 and it formated clean. Am I wrong ?? My
mountlist is the default RES2: entry for the scsi with 20 buffers a interleave
of 0, 4 surfaces, 17 blocks per track, lowcyl = 0 highcyl = 1, bufmemtype I
changed to 4 but no diff, reserved = 2, unit = 3. See anything wrong? Lets
hope its me and not a problem with the 2090. Unless another new driver fixes
it.
Paul Montgomery
Paul, this might not be the solution to your problem, (nice start, eh?) but
here are the settings I used for my 40meg Miniscribe: Drive type = 0 (user
defined), 6 (SIX!) sufaces, 17 block per track, 808 cylinders. Formatted fine
first time. (this is an ST506 drive, though.) I also had a 50 meg SCSI drive
connected at the same time, and both were running fine, though I never tried
having two screens at the same time. The SCSI is now on another 2000, so I
can't test that anymore. Anyway, I noticed something strange in my RES2: entry
in the mountlist: it has a Reserved = 0 and not 2! Why? I don't know but it
seemed to work just fine. Hope any of this is usefull.
Khalid.
Khalid,
I hope I pronounced that right. I too noticed the reserved of zero in the
mountlist and changed it to 2 hoping that that was the problem. Unfortunatly,
it didnt change the problem. The number of surfaces is supposed to be equal to
the number of heads on the drive. Your miniscribe probably has 6 heads, the
ST251 has 6 but according to the segate manual the ST251N has only 4. So, I
used 4. The st251N has 820 cyls according to the manual but mine would only
format to 807. I am told that because the drive is a scsi drive, the scsi
controller reserves some of the cyls for its own use and that I cant get at all
of them, so not being able to access beyond 807 on the format would maybe make
sense. So I preped the drive saying that it had 807 and it formatted fine. I
do appreceiate your responding. Did you say you had 2 A2000's ? I had a
dickens of a time just getting one. The dealers around here allways get there
orders filled about 2 years after everybody else in the country it seems.
Thanks again.
Paul
Paul,
Is your drive a 40 meg? If so then there must be something wrong with
one of your settings. 807 cyl x 4 heads x 17 blocks per track x 488 bytes per
block gives 25.5 megs of storage and not 40. Maybe you should set your blocks
per track to 25 and reformat. If that works then you would get around 37 megs,
almost right. Or if you format it with 6 sufraces, you would get exactly 40
megs. If your drive is actually a 25 meg then disregard the previous stuff.
Khalid.
P.S. About my 2 A2000s; I got them a the PC World show in London, U.K. They
were quite in abundance there, and at quite good prices.
Khalid,
Yes its a 40 meg drive. a seagate st251N. The manufacturer's docs say it
has four heads but doesnt mention tracks. So I guess I should use 25 ? The
disk doesnt have anything on it so I guess I could try real soon now. Thanks
Paul
Well, Paul. I think it would be worth a try. I just got my hands on a Seagate
manual, and it seems that the ST251N is an RLL drive, which means that it must
have 25 blocks per track, since RLL squeezes more blocks per track than MFM
(the usual storage method). The usual problem (as Steve mentioned) would be
that you would have to do the low level formatting on another computer, since
the A2090 does not do it.
Khalid.
Paul, I had problems using my NEC 5146 (SCSI) with my 2090. I removed the OMTI
5100 ST506->SCSI board and used it as an ST506 drive. Seemed to work fine
then. If you could use it as an ST506 vise a SCSI, I think your problems with
R/W errors would go away. Seems to me, I've only heard of people having those
problems with SCSI interfaced drives.
<Glenn
Glenn,
I may end up doing as you say. I hope not cause I bought the scsi to
experiment with it versus a st506 drive of equivalent access times. To see if
in the amiga world it makes any difference to pay the bigger bucks for the
faster transfer rates. With the 2090, I havent noticed a large difference in
real world usage between the two drives. ( when the scsi is usable ). I wonder
though if using the SDP or other faster controllers the difference would be
more pronounced. If not, whats the use in getting a scsi drive ?
Paul
Paul, exactly. It isn't the hardware, but the software (filesystem) that
limits the speed of data transfer to and from the HD. So, for now, it isn't
worth the extra bucks for SCSI. In the future with SDP, perhaps you will need
a SCSI drive so that you aren't limited.
<Glenn