16 Mar
2022
16 Mar
'22
6:25 p.m.
I was visiting a new thrift store and saw a disk pack they had. I joked
that mine are just fun display/conversation pieces.
Do the giant drives suffer the same head crash issues that a bad zip disk
can do or are these safe if someone actually wanted to see what was on them?
16 Mar
16 Mar
7:01 p.m.
On 3/16/22 18:25, John Herron via cctalk wrote:
I was visiting a new thrift store and saw a disk pack
they had. I joked
that mine are just fun display/conversation pieces.
Do the giant drives suffer the same head crash issues that a bad zip disk
can do or are these safe if someone actually wanted to see what was on them?
I vividly recall a log by an operator who had a bad CDC 844 pack who
proceeded to destroy 5 drives and 3 additional packs. It was detailed
enough that it read like Gerard Hoffnung's "Bricklayer's Story".
https://monologues.co.uk/Sketches/Bricklayers_Story.htm
Be careful.
7:28 p.m.
I vividly recall a log by an operator who had a bad
CDC 844 pack who
proceeded to destroy 5 drives and 3 additional packs. It was detailed
enough that it read like Gerard Hoffnung's "Bricklayer's Story".
When I was testing one of my RL02 drives I had a head skid on the disk.
Problem was the air filter was so clogged there wasn't enough air to
allow the heads to fly.
Replaced filter which allowed me to read the damaged pack with the worn
down heads, then replaced the heads with a spare set. The heads
themselves were worn to the point where they were angled....
Disclaimer: This drive and pack came from a Solarex plant where they
controlled the silicon wafer cutters. In other words silicon dust
everywhere.
Oi.
17 Mar
17 Mar
6:27 a.m.
On Mar 16, 2022, at 10:28 PM, Chris Zach via cctalk
<cctalk at classiccmp.org> wrote:
Huh? The way I've always understood it is that heads fly from the air entrained by
the disk surface as it spins, not from air blown through the drive via the air filters.
And clearly that is true for modern drives, since they are sealed.
paul
I vividly recall a log by an operator who had a
bad CDC 844 pack who
proceeded to destroy 5 drives and 3 additional packs. It was detailed
enough that it read like Gerard Hoffnung's "Bricklayer's Story".
When I was testing one of my RL02 drives I had a head skid on the disk. Problem was the
air filter was so clogged there wasn't enough air to allow the heads to fly.
6:33 a.m.
Modern disks still have a filtration system and airflow within the disk.
Air usually gets sucked from the edge then through the spindle and out
the center. In this case I think the spinning created a lower pressure
area where the heads were, resulting in the heads flying too low.
I'll re-look at the RL02 but I believe air was not pulled in from
outside but recirculated from behind the heads under the unit to the
center spindle where it came out, into the center of the pack and across
the heads. Closed system when the lid was closed.
C
On 3/17/2022 9:27 AM, Paul Koning wrote:
On Mar 16, 2022, at 10:28 PM, Chris Zach via
cctalk <cctalk at classiccmp.org> wrote:
Huh? The way I've always understood it is that heads fly from the air entrained by
the disk surface as it spins, not from air blown through the drive via the air filters.
And clearly that is true for modern drives, since they are sealed.
paul
I vividly recall a log by an operator who had a
bad CDC 844 pack who
proceeded to destroy 5 drives and 3 additional packs. It was detailed
enough that it read like Gerard Hoffnung's "Bricklayer's Story".
When I was testing one of my RL02 drives I had a head skid on the disk. Problem was the
air filter was so clogged there wasn't enough air to allow the heads to fly. 
7:32 a.m.
On 3/17/22 09:33, Chris Zach via cctalk wrote:
Modern disks still have a filtration system and
airflow within the disk.
Air usually gets sucked from the edge then through the spindle and out
the center. In this case I think the spinning created a lower pressure
area where the heads were, resulting in the heads flying too low.
I'll re-look at the RL02 but I believe air was not pulled in from
outside but recirculated from behind the heads under the unit to the
center spindle where it came out, into the center of the pack and across
the heads. Closed system when the lid was closed.
No RL disk I ever had closed tight enough to be considered a Closed
System with lid down. :-)
bill
8:26 a.m.
------ Original Message ------
From: "Bill Gunshannon via cctech" <cctech at classiccmp.org>
To: cctalk at classiccmp.org
Sent: Thursday, 17 Mar, 2022 At 14:32
Subject: Re: Does anyone/museum test disk packs?
On 3/17/22 09:33, Chris Zach via cctalk wrote:
Modern disks still have a filtration system and airflow within the disk.
Air usually gets sucked from the edge then through the spindle and out
the center. In this case I think the spinning created a lower pressure
area where the heads were, resulting in the heads flying too low.
I'll re-look at the RL02 but I believe air was not pulled in from
outside but recirculated from behind the heads under the unit to the
center spindle where it came out, into the center of the pack and across
the heads. Closed system when the lid was closed.
No RL disk I ever had closed tight enough to be considered a Closed
System with lid down. :-)
bill
That's worth noting. I have one that's in dire need of restoration, with
a sizable chunk missing off the lid by the back hinges. Makes me less
worried about fixing it with tape and cereal boxes
Cheers,
Josh rice
12:03 p.m.
Well yeah sealed is relative but the more time you have the lid open the harder the filter
needs to work.
Oddly enough the diablo 44 just pulled outside air thru a filter. Guess what did not last
long
On March 17, 2022 11:26:14 AM EDT, Joshua Rice via cctalk <cctalk at classiccmp.org>
wrote:
------ Original Message ------
From: "Bill Gunshannon via cctech" <cctech at classiccmp.org>
To: cctalk at classiccmp.org
Sent: Thursday, 17 Mar, 2022 At 14:32
Subject: Re: Does anyone/museum test disk packs?
On 3/17/22 09:33, Chris Zach via cctalk wrote:
Modern disks still have a filtration system and airflow within the disk.
Air usually gets sucked from the edge then through the spindle and out
the center. In this case I think the spinning created a lower pressure
area where the heads were, resulting in the heads flying too low.
I'll re-look at the RL02 but I believe air was not pulled in from
outside but recirculated from behind the heads under the unit to the
center spindle where it came out, into the center of the pack and across
the heads. Closed system when the lid was closed.
No RL disk I ever had closed tight enough to be considered a Closed
System with lid down. :-)
bill
That's worth noting. I have one that's in dire need of restoration, with
a sizable chunk missing off the lid by the back hinges. Makes me less
worried about fixing it with tape and cereal boxes
Cheers,
Josh rice
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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