With your assumptions. The RD53 has 138672 logical blocks. 138672 * 512
= 71,000,064. This is less than the actual physical capacity because the
controller reserves some amount of space for bad block tables and
replacement blocks. See the attached document, chapter 3, for details.
The same is true of the RD52. It is actually 512 cylinders, not 480, and
the visible capacity is a subset of the physical capacity. There were
two different vendor drives used, one with 8 surfaces, one with 7, and
the capacity is limited to what the 7 surface drive could hold.
/Bob Supnik
On 5/7/2015 12:00 PM, simh-requ...@trailing-edge.com wrote:
Message: 1
Date: Wed, 6 May 2015 22:29:24 -0500
From: Seth Morabitolists+s...@loomcom.com
To:simh@trailing-edge.com
Subject: [Simh] RD53 image size
Message-ID:20150507032924.ga21...@loomcom.com
Content-Type: text/plain; charset=us-ascii
Hello all,
I'm trying to build an RD53 image that I can transfer to a real RD53
on an 11/73. I did the same with an RD52 on another system and it
worked perfectly, but I noticed something odd about the RD53.
The RD52 image size is 30,965,760 bytes. That maps exactly to 480
cylinders, 7 heads, 18 sectors/cylinder, 512 bytes per sector.
(480 * 7 * 18 * 512 = 30965760).
The RD53 image that SIMH generates, on the other hand, is 71,000,064
bytes. This does not match what I would expect. The RD53 is 1024
cylinders, 8 heads, 17 sectors/cylinder, 512 bytes per sector. That
should be 71,303,168 bytes, shouldn't it?
Is something wrong with my math, or one of my assumptions?
-Seth
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|DIGITAL EQUIPMENT CORPORATION |
|MAYNARD, MASSACHUSETTS |
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| ENGINEERING SPECIFICATION DATE: 09-JUN-1986 |
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| Title: RQDX3 Engineering Specification |
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|Revisions |
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| Rev |Description | Chg No | Orig | Date | Appd By | Date |
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| A |First Release || | | | |
| B |Add New Devices || | | | |
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| Eng:| Appd: | Size | Code | Number | Rev |
| | |---|---|-|-|
| Nick A. Warchol | | K| SP | RQDX3-0-DBF
