MSCP SCSI controller speed

Allison ajp166 at bellatlantic.net
Tue Nov 8 08:27:47 CST 2005



>
>Subject: Re: MSCP SCSI controller speed
>   From: "Tim  Shoppa" <tshoppa at wmata.com>
>   Date: Tue, 08 Nov 2005 08:52:24 -0500
>     To: <cctalk at classiccmp.org>
>
>>From a post I made to the PDP-11 newsgroups in the previous
>millenium:
>
>The benchmarks were done under RT11FB 5.7 doing 1, 2, 4, 8, 16,
>32, and 64 block-at-a-time READW's and WRITW's to 16384-block
>data files.  A KDJ11B (PDP-11/73) CPU with 2 Megabytes of Clearpoint
>non-PMI memory was used for the bencharmks.  With the SCSI
>controllers a Barracuda 7200 RPM ST15230N drive was used; with
>the RQDX3 a RD52 drive was used.
>
>
>Here are the peak data rates measured for read and write 64
>blocks-at-a-time:
>
>
>                   Read           Write
>                  ----------     ----------
>Andromeda SCDC    2.298 MB/s     1.131 MB/s
>CMD CQD440        2.397 MB/s     1.525 MB/s
>CMD CQD220        1.418 MB/s     0.882 MB/s
>CMD CQD220A       2.088 MB/s     1.409 MB/s
>DEC RQZX1         1.379 MB/s     1.097 MB/s
>Viking QDT        0.846 MB/s     0.704 MB/s
>DEC RQDX3         0.164 MB/s     0.161 MB/s
>

>From using the RQDX3 on PDP-11 and microVAXII against the 
Viking QDT and CMD220 I can say the RQDX is glacially slow.


Allison





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