15 Sep
2009
15 Sep
'09
6:02 p.m.
Eric Smith said the following on 9/15/2009 8:49 PM:
Dave Mabry wrote:
That was certainly the most versatile configuration. It was an easy way
to get single density. But, if all you were using was the Intel
software/operating system then there really was no reason to have single
density. The internal drive was agonizingly slow in single density when
being controlled from the IOC. If, on the other hand, you were using
CP/M then there was a definite advantage to being able to write single
density for interchange with other systems since it was the only real
standard format.
I used Intel Development Systems a lot and the only reason I had to use
CP/M in the professional world was to create documentation in Wordstar.
For programming my entire company used the Intel tools with ISIS-II.
Today I have several working MDS configurations, some with the internal
drive converted to double density, some not. I have never had anyone
want me to copy them ISIS-II or Intel s/w on single density. However, I
haven't used double density at all for copies of CP/M software.
Dave
There was an option Intel sold that upgraded the
internal 801 drive
to work in a double-density mode. That included a two-board multibus
set that could control up to four drives. Normally that two-board
set controlled up to two external two-drive packages. So up to four
double-density single-sided drives total. They also sold a special
cable that allowed that internal two-board-set to control the one
internal drive. That cable went from the interface board of the
two-board set to two connectors. One connector is the 50-pin edge to
the 801 drive directly. The other connector is a 37-pin D-type
connector that attaches to the back panel of the MDS and is for
controlling a two-drive external box. There are other permutations,
but that is the most common way to get the internal drive to be
double-density.
Most MDS systems I used or saw back when they were current only
used
double-density on the external drives and not the internal, because
the double-density controller would NOT read or write single-density
disks, and most people still needed or wanted that capability.
Eric