On 2021-11-16 5:08 p.m., jim stephens via cctalk wrote:
On 11/16/2021 2:20 PM, Al Kossow via cctalk wrote:
On 11/16/21 2:08 PM, Murray McCullough via cctalk wrote:
Did the 4004 chip start our interest in microcomputing?
no
I got interested in microprogramming before it was hijacked as a a term
for such devices. It's generous at best to apply that term to a 4004
anyway.
In 1971 firmware and the like still was still very much something that
was used in conjunction with system design. A group was very active,
SIGMicro to share techniques. Only after most microprogramming vanished
into a black hole in the silicon did it taper off.
I'm glad some amount of that discipline has emerged in that context, and
not applied to small ceramic chips with gold legs.
thanks
Jim
Only looking back now at the price and speed of main memory, I can see
micro-programming advantage. Having the word settle on 8 bit bytes;
(my vote was for 10 bits : 2 BCD digits + sign flag + end flag)
You have a severe lack opcode space as every thing is n+ bytes, compared
to when you could design the CPU to what ever word sized you needed and
room for micro-coded ops
and full alu rather than ADD DCA AND OPERATE.
Ben.
Back then you touch the hardware.
