[cctalk] Re: Disk-pack-based drives at LCM

[Chris Zach via cctalk]

Last time I worked with large pack drives was the three RM03's in 2003 
or so before I sent AI to LCM. One of the drives had dirty heads and I 
cleaned them with isopropyl. Mounted a scratch pack and it exploded. 
Other two drives were clean and worked fine before powering down, 
parking, and putting away.

CDC drives have glue or something that is not compatible with alcohol. 
RL01/02/RK05/RK03's do not seem to have this issue, I have 
cleaned/replaced those heads without issue.

One important thing: Check the air filter before doing anything. On one 
of my RL02's the heads were sanded down like cheese wedges and it took 
me a bit to realize the filter was plugged and not enough air was going 
over them to allow them to fly properly. Then again that system was used 
at Solarex, where they cut wafers for solar panels. Filter was choked 
with silicon dust. Oi..

CZ

On 6/4/2023 7:07 PM, Robert Ollerton via cctalk wrote:
cp-v at the LCM,  system and swapping on 300MB packs.



On Sun, Jun 4, 2023 at 3:16 PM P Gebhardt via cctalk <cctalk@classiccmp.org>
wrote:

Hi Rod,

I don't blame them either! Operating these drives means having access to
spare heads, alignment equipment and and alignment pack - not taking into
account the work to be put in all of this!
Anyway, thanks for sharing your anecdote with us :)
Greetings,
Pierre


I can't say I blame them.  It was a lot of work to get a drive running
after a head crash.  If it was a bad crash, there >could be extensive
cleaning to be done followed by replacing one or more heads.  Then the new
heads had to be >aligned.  If you hadn't cleaned thoroughly enough, you
risked damaging the expensive alignment disk.
Once I came back from lunch to see the operators had 3 drives open.  They
kept swapping a disk pack which was >giving I/O errors to new drives and
were crashing heads along the way due to the damaged disk pack.  I stopped
them before they spun up the pack on a 4th drive.  That wasn't as bad as
the time one of them dropped a disk pack >and bent platters.  That ripped
heads completely out of the mounting mechanism.
Ah, the good old days!

Rod
On Jun 2, 2023, at 2:51 AM, P Gebhardt via cctalk <cctalk@classiccmp.org>
wrote:
Hi all,

I just came across pictures on the LCM website about their SDS Sigma
installation there.
On the pictures, one can see 10-platter disk packs in the corner and
stored on the disk drives.
Did the LCM ever had these in operation, either for data retrieval or
even demo purposes?
I know of the Jim Austin Computer museum where they fixed a CDC 9766
drive but it suffered
a head crash after a few hours according to their description which led
to giving up the operation
of these drives.

Greetings,
Pierre


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