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<div class="moz-cite-prefix">On 23-Mar-20 13:35, Robert Armstrong
wrote:<br>
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<pre class="moz-quote-pre" wrap="">Timothe Litt <a class="moz-txt-link-rfc2396E" href="mailto:litt@ieee.org"><litt@ieee.org></a> wrote:
KS10 ... The 8085 code is crammed into UV EPROMs.
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Was all of the KS CFE code in EPROM? </pre>
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<p>Yes, it is. There are a couple of microwords in the CRAM that
deal with console responses (single step, console interrupts for
the serial lines). But that's it.</p>
<p>The KS can, and does initiate some bus cycles to get an RH11 tape
or disk to load a record into PDP-10 memory. That record contains
the CRAM ucode. The 8080 reads it from -10 memory and load the
CRAM. And once it's a PDP-10, the next stage of boot (again, a
few instructions) loads the monitor bootstrap.</p>
<p>The CSL has no dedicated mass storage - and that was an issue of
reliability even more than cost. The other issue is that CSL
didn't have a lot of space. At the time, you wouldn't put DRAM on
an 8085. (And if you did, you needed yet another few chips of
refresh controller, address decoders, etc.) SRAMs were small and
expensive. And once you took up the space for an EPROM socket,
you might as well make it big enough to hold everything...</p>
<p>One nice thing about the KS is that it was very well documented.
(Had to do something with the time while internal politics
prevented its release before the 780...) There's a copy of the
technical manual on bitsavers, which you can read for more
entertainment.<br>
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<pre class="moz-quote-pre" wrap=""> On the 730 only a small kernel of 8085 code (about 2K as I remember) was in ROM/EPROM and the rest of the 8085 memory was RAM. The first thing the 8085 did at power on was to load the rest of the 8085 code from the TU58. That made it possible to issue updates to the CFE code as well as the microcode.
Bob
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