#HD Max Transfer Settings
6 messages in this thread
I need some help here with an IDE drive in an A4000. The drive is an IBM (OEM)
170 Meg model H3171-A2. It has 984 Cylinders, 10 Heads, and 34 Blocks/Track.
I installed the drive with HDToolBox (which correctly read the config from the
drive), formatted with FFS and all seemed fine. I installed WB3.0 plus lots of
apps and most things worked OK.
The PROBLEM emerged when I tried copying over some large programs & files
(>200K). The data is fine if the file is written with multiple small writes,
but not with one big continuous write. (eg. image saved from paint program –
fine : image file copied from RAM: to HD: – not OK)
This leads me to suspect that the Max Transfer rate may need changing
(currently $ffffff). The question is:- which way should it be changed (up or
down) and what sort of value would anyone suggest? Or what else may be to
blame?
This is not a well documented area, so any help would be much appreciated.
Martin Kay, ZEN Computer Services, UK
Martin,
You are correct in your diagnosis – the MaxTransfer value is most
likely the culprit.
Try changing the value to $1ffff and see if things work well. If not,
change it to $ffff, which _should_ work for all drives.
Hope this helps….
– BobR
Bob…
You seem to know your stuff on HDs soooooo. I have installed a second HD in my
A3000
(internally) as SCSI device #1 (the original HD is device #6). It low level
formats via HDtools okay and the partitions appear when I reboot. I then
format the partitions ok and can write to them . Now the p problem. When I
reboot the drive doesn't appear to be mounted (I did select the automount
function). This is a Maxtor 50 meg dri drive partitioned into two 22meg
partitions.
I just thought of something from way back. Is it possible that this is one of
those slow spin up drives that need some special magic to be recognized? Any
help/suggestions will be greaatly appreciated.
..Carl
Carl,
If the problem is because of "slow spinup", then the problem would not
occur on a warm boot (ctrl-amiga-amiga), but would when first powering on
the machine. If that is the case, then there is a control flag in the
3000's battery-backed memory that will tell the OS to compensate for slow
drives. I believe that there is a utility called Battmem that can be used
to turn that control flag on.
Sorry I can't be more specific, as I do not have a 3000 and don't
remember the details.
Hope this helps….
– BobR
Bob…
Slow spinup must not be the problem because it occurs on a warm boot. Now I
wonder what it really is. :^(
..Carl
MK >>I need some help here with an IDE drive in an A4000. […] The
PROBLEM emerged when I tried copying over some large programs & files
(>200K).<<
This is a very common problem. The default Maxtransfer rate is setup for
a SCSI drive, and not for IDE drives.
The IDE's have different limitions, and one is the maximum amount of data
that can be sent in one write. I believe the standard allows for at least
128K writes. However, most IBM IDE interfaces only do 64K writes and
don't use the MULTIPLE READ & MULTIPLE WRITE commands — which has allowed
IDE manufactures to be a little sloppy with the standard.
Using HDToolBox, change the value of MaxTransfer to equal '0x1fe00', for
each partition.
This will alter the maximum size of the data packets the Amiga will send
to the drive at a time to 128K (minus 512 bytes).
Also, some IDE drives also have smaller RAM buffers/caches built into
them, and can't handle the larger (>64K) packets the Amiga can feed them.
Ron.
– ap'ing with AP. (Eagles may fly, but weasels aren't sucked
into jet engines.)