20 Feb
2011
20 Feb
'11
8:14 p.m.
I'm trying to fix up an RL02 that throws constant errors in XXDP's ZRLMB1
test from head 1.
In,
http://www.bitsavers.org/pdf/dec/disc/rl01_rl02/EK-RL122-TM-001_techAug82.p…
"RL01/RL02 Technical Manual"
on page 58, it shows upper head (1) and lower head (0).
But,
http://www.bitsavers.org/pdf/dec/disc/rl01_rl02/RL02techDescr.pdf
throughout refers to the upper head as 0 and the lower as 1.
Which "1" is ZRLMB1 refering to? ;-)
Chris
--
Chris Elmquist
22 Feb
22 Feb
1:05 p.m.
At 10:14 PM -0600 2/20/11, Chris Elmquist wrote:
In,
http://www.bitsavers.org/pdf/dec/disc/rl01_rl02/EK-RL122-TM-001_techAug82.p…
"RL01/RL02 Technical Manual"
on page 58, it shows upper head (1) and lower head (0).
But,
http://www.bitsavers.org/pdf/dec/disc/rl01_rl02/RL02techDescr.pdf
throughout refers to the upper head as 0 and the lower as 1.
I don't know the answer, but I certainly see the confusion.
A later revision (-002) of that manual updates the Figure 1-6 on page
I/1-9 and explicitly labels the heads upper (1) and lower (0) while
retaining the text throughout that refers to them as the opposite of
that. Interesting and confusing!
I guess you'll have to measure to find out.
John
23 Feb
23 Feb
10:49 a.m.
A later revision (-002) of that manual updates the
Figure 1-6 on page
I/1-9 and explicitly labels the heads upper (1) and lower (0) while
retaining the text throughout that refers to them as the opposite of
that. Interesting and confusing!
I guess you'll have to measure to find out.
I wonder if the heads were originally refered to as the 'up' and 'down'
head. That would have been conventional at one time and refers to the
direction that the heads face. So the 'up' head is the lower one, the
'down# haed is the upper one.
If this got edited by somebody unfamiliar with the terms, the 'up' head
may well have become the 'upper' head, hence the confusion
-tony
24 Feb
24 Feb
3:13 p.m.
On 24/02/2011 5:49 AM, Tony Duell wrote:
What hapens when a RL02 is installed upside down :-)
A later
revision (-002) of that manual updates the Figure 1-6 on page
I/1-9 and explicitly labels the heads upper (1) and lower (0) while
retaining the text throughout that refers to them as the opposite of
that. Interesting and confusing!
I guess you'll have to measure to find out.
I wonder if the heads were
originally refered to as the 'up' and 'down'
head. That would have been conventional at one time and refers to the
direction that the heads face. So the 'up' head is the lower one, the
'down# haed is the upper one.
If this got edited by somebody unfamiliar with the terms, the 'up' head
may well have become the 'upper' head, hence the confusion
-tony 
25 Feb
25 Feb
6:46 a.m.
On Thursday, February 24, 2011, Doug Jackson wrote:
On 24/02/2011 5:49 AM, Tony Duell wrote:
All of the bits fall off of the platters.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
I wonder if the heads were originally refered to
as the 'up' and
'down' head. That would have been conventional at one time and
refers to the direction that the heads face. So the 'up' head is
the lower one, the 'down# haed is the upper one.
If this got edited by somebody unfamiliar with the terms, the 'up'
head may well have become the 'upper' head, hence the confusion
-tony
What hapens when a RL02 is installed upside down :-)
12:49 p.m.
On Friday (02/25/2011 at 08:02PM +0000), Tony Duell wrote:
But maybe this would keep the (normally) upward facing head from
crashing then?? :-)
I still don't know which head is which but I have determined that neither
head is completely borked in the drive I am working on. I don't start
getting errors until out around cylinder 490 or so... before that,
it reads without error. So, that is much more hopeful. Just need to
run through the cal / adjustment procedures and see if I can't bring it
back into line.
Part of that process will reveal to me which head is which... as I will
see the results of the head the software selects on a scope.
Thanks for the input on the issue though. It is appreciated.
Chris
--
Chris Elmquist
What hapens when a RL02 is installed upside down :-)
You have a devil of a job getting the pack and pack cover in. The latter
is likely to fall out before you can close the cover.
26 Feb
26 Feb
7:53 a.m.
On Friday (02/25/2011 at 08:02PM +0000), Tony Duell wrote:
But maybe this would keep the (normally) upward facing head from
crashing then?? :-)
Alas not, the head load springs easily overcome any force of gravity.
What hapens when a RL02 is installed upside down :-)
You have a devil of a job getting the pack and pack cover in. The latter
is likely to fall out before you can close the cover.
I still don't know which head is which but I have determined that neither
head is completely borked in the drive I am working on. I don't start
Can't you work this out from the schematics? Trace the head sleect signal
from the cotnroller (through shift registers IIRC) to
the drive and then
see which of the 2 heads it selectes in each state.
'All' you have ot do
then is dtermine which head is plugged into whcih connector on the R/W PCB.
-tony
4831
days inactive
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ard＠p850ug1.demon.co.uk -
chrise＠pobox.com -
doug＠doughq.com -
dundas＠caltech.edu -
pat＠computer-refuge.org