how fast were drum memories?
useddec at gmail.com
Fri May 11 01:18:45 CDT 2018
The good old days...
I recall the Q-7 drums would take about 15 minutes to come to a stop when
turned off, and would power up in seven seconds or less. Surge current was
around 115 amps?
On Thu, May 10, 2018 at 3:46 PM, Mike Loewen via cctalk <
cctalk at classiccmp.org> wrote:
> On Thu, 10 May 2018, Al Kossow via cctalk wrote:
> On 5/10/18 10:37 AM, Al Kossow via cctalk wrote:
>>> On 5/10/18 9:29 AM, Paul Koning via cctalk wrote:
>>> One that comes to mind is the DEC RS04. It spins at roughly 3600 rpm (a
>>>> hair less, so obviously a 2 pole induction motor running off 3-phase 60 Hz
>>> Vermont Research drums (model 1175B) spun at 3450 rpm 3ph 220v, The HP
>>> 2773 on the 2000A TSB was from VR so I expect RPM
>>> would be similar for most drums of similar diameter.
>> Just checked, and the LGP-30 and RPC-4000 drums are both listed as 3600
> The drums on the SAGE system (12 on each side), are listed as follows:
> Diameter: 10.7"
> Width: 12.5"
> Weight: 105 lbs (cylinder, only), 450 lbs for entire drum assembly
> Speed: 2914 rpm
> Heads: Up to 12 R/W bars, with up to 40 heads on each bar, 1
> erase bar
> 6 pairs, one for Compuuter-to-Drum (CD), one for
> Other-than-computer-to-Drum (OD)
> Head spacing 0.3" apart on each bar
> Drum Layout: 2048 registers on 33 channels (tracks), 6 fields
> Channel spacing is 0.050"
> Access Time: Maximum 20ms, average 10ms
> Write Current: 110ma
> The R/W bars are arranged in pairs (CD and OD) so that I/O devices can
> access the drum independently of the computer.
> More than you ever wanted to know about SAGE drums (thanks, Al!):
> Here's one of the earlier style R/W heads:
> Mike Loewen mloewen at cpumagic.scol.pa.us
> Old Technology http://q7.neurotica.com/Oldtech/
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