14.003 2 How did Woz invent the Apple computer? C.T.: You've seen the report; how much is accurate?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
14.003 2 How did Woz invent the Apple computer? C.T.: You've seen the report; how much is accurate?
Woz: The author of the report I received from you is wrong when he says no ROM
of large size was assembled by hand. I could never afford an assembler for the
6502 which I bought for $20.
First, I connected the 6502 to Static RAM and a video terminal of my own
design. I then wrote a short "monitor" program to watch the keyboard and
display characters, both under interrupt and polled. We didn't have 256 byte
PROMS, just 256x4 PROMS at that time. I used two of the ones we burned for
calculator development at HP. The first hardware bringup had a few frustrating
hours but I got it working with polled keyboard that night.
I then wrote a 256 byte "Monitor" program which watched the keyboard for
hex data entry (address:data data data) and hex display and program initiation
("Run"). I got very good at typing in hex and very very good at checking data
entry carefully, character by character. I still can't read a credit card
number without a high expectation of mistake, but I have good habits to this
day.
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