Exploring Binary On My Apple II
Copyright © 2008-2013 Exploring Binary
I’m reading Steve Wozniak’s 2006 book “iWoz” and this line got me wondering about my own Apple II:
“In every speech I give, I talk to people who are still running Apple IIs, and they say those machines are still running after this many years.”
So I got it out of the attic and powered it up. The dozen or so dead keys notwithstanding, it still works — after 30 years!
Getting The Monitor To Work
I was expecting not to have the cable or connector I needed to hook the computer up to a TV (as I recall, there was a splitter that attached from the video cable to the TV’s VHF inputs). Also, I was wondering if I had a TV with the right inputs. It turns out I had what I needed.
The video cable was already attached to the computer, inside the case to an RF modulator. Hooking that to the TV’s video input did not work. After looking online for documentation (I no longer have the manuals), I found a copy of the “Apple II Basic Programming Manual”; on page 5 I saw this:
“If you have a color (or black and white) monitor, just connect the appropriate cable from the jack marked “VIDEO OUT” (on the rear of the Apple II) to the input of the monitor.
If you have an ordinary TV, you will have to install an RF modulator.”
I never used a monitor back in the day — just a TV. So all I did was move the cable to the rear input — and I got video!
Getting Into BASIC
All that appeared on the screen was the “Apple ][” logo. My disk drive was attached, and it was spinning (there was no floppy disk in it — I don’t have those either). It occurred to me to remove the floppy drive controller card so that the computer would boot into ROM BASIC. I powered up again and, bingo!
A Partially Working Keyboard
Unfortunately, many keys did not work (among others: a, b, i, o, y, 4, -, =, and ,). I opened the bottom of the case to see if there was anything obviously wrong, but I didn’t see anything (surprisingly though, there was no dust inside the case).
An Example BASIC Program
I wanted to make some binary related program using the available keys. Luckily, I had double quotes and the question mark, so I could print stuff. I also had exponentiation (‘^’), addition, and division, which were enough to make the small program pictured above (the picture shows our old TV, before I realized that with correct attachment, it would work on our newer TV):
- Line 10: Prints “Rick Regan exploringbinary.com 2/5/12”, or the closest thing to it with missing keys and all caps.
- Line 20: Prints 232, which displays in scientific notation, correctly rounded to eight significant digits, as 4.2949673E+09.
- Line 30: Prints 2-32, which displays in scientific notation, correctly rounded to nine significant digits, as 2.32830644E-10.
- Line 50 (remember my ‘4’ key doesn’t work): Prints 20 + 22 + 23 + 25 + 27 + 212 + 215, which corresponds to the binary representation of 37037.
- Line 60: Prints 2.2250738585072011/10308 (which is how I had to enter 2.2250738585072011e-308 without a minus sign). It overflows, but at least it doesn’t hang!
Is the Apple II Really a Computer?
My kids watched me as I did this. “Where’s the mouse?” “How do you click on things?” “Does it play Angry Birds?” The problem was I kept calling it a computer, but it wasn’t like any computer they’d ever seen.