donw@beaujolais (Don White) (03/08/88)
[Leane iter gobbles]
We (meaning all of us) need access to some thorough diagnostic for our
Amigas!! Its very frustrating to have a system with intermittent failures
using programs like garrison (Can anyone tell me WHY my 40$ game SOMETIMES
fails? I've heard other people complain, but WHY does it fail?) A mutli-
level RAM test would sure put my mind to rest!! It should detect address
errors as well as timing problems involving different patterns written to
RAM.
The other major problem is drive to drive compatability. If a diag-
nostic disk is/was available, it would be great to run it through every
month or two to check for alignment drift (both radial and axial), and
speed (can be checked with Marauder).
Radial drift affects the alignment of the heads over a chosen track.
This is THE MOST LIKELY problem when one drive can read a disk and another
can't. If one drive is writing tracks a little to close to the hub and
another drive is reading a little to far from the hub, they can both be
marginally in specs but they may not work with each other. The unfortunate
problem with this adjustment is that it requires a STANDARD disk. I
remember 51/4" standard disks cost about 100$. They are made with ANALOG
equipment to very fine tolerances. I don't know what is available for
our stiffies.
Axial drift is fairly unlikely, but it is possible. It occurs when
the drive head is TWISTED with reference to the tangent of the tracks.
Speed is often a problem from one drive to another. The amiga drives
read and write whole tracks at once. This means that timing is not as
critical as on other systems which have to fit sectors in their place with
a fair degree of accuracy. But if you are running too slow or too fast, it
can't still cause garbling.
I vaguely remember checking something called azimuth on shugart drives
but I don't recall whether that would be applicable to a drive that writes/
reads whole tracks at a time.(I thought is had something to do with sectors.)
P.S. If no PD ram test or disk tests are available, I have some ideas
for a self relocating ram test... Does anyone have enough disk savy to
maybe write a disk excerciser? Does anyone know where to get diagnostic
an ANALOG diagnostic disk for 3 1/2" drives? Is there any joy in mudville?
Don White
Box 271177
Concord, CA.
94527-1177
{hplabs | ucbvax | oliveb | ihnp4 } !zehntel!donw
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