Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!aramis.rutgers.edu!paul.rutgers.edu!jac From: jac@paul.rutgers.edu (Jonathan A. Chandross) Newsgroups: comp.sys.apple Subject: Re: RE: Hmm... Message-ID: Date: 16 Jul 89 02:27:30 GMT References: <8907121655.AA02954@decwrl.dec.com> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 46 Question: ; o Is it possible to use an Apple ][e without a disk card in slot ; 6? Without a disk card at all? (I have a //c, so I've never been ; able to try :)...) If so, can it be "booted" from another ; computer... say a Vax or another Apple? secrist@msdsws.enet.dec.com ("Richard C. Secrist") responds > Yes, it simply boots into Applesoft BASIC, where you can use cassette > for I/O. Of course if you burned your own ROMs it could boot into > something else. I worked for some biophysicists a number of years ago doing instrument computerization. We used an Apple ][+ with a custom ROM board in slot 0. This board has (6) 2716's on it. We used to write our software in Basic (with assembly where needed) and ROM it. When the thing powered up it would boot from the ROM card. We used this to drive all sorts of strange gadgetry. You may laugh, but at the time it was the cheapest (and easiest) way to computerize an instrument. The Apple had slots which we used for: an 16 bit DAC/ADC board and the ROM board I mention above. And we often used the paddle port when we needed a lot of buttons. You see, the paddle port gives a value proportional to the resistance of the paddle. If you replace the potentiometer with a bunch of switches, each of which has a different resistor attatched to it, you can sense a bunch of switches very cheaply: Pushbutton switch __|__ Resistor 1 +5 |--o o----/\/\/\/\----------| | | | |---| __|__ Resistor 2 |------- To paddle input |--o o----/\/\/\/\----------| Say R1 = 50K and R2 = 150. Then you'll have values of (approx) 255 when R2 is closed and about 80 when R1 is closed. Obviously, you can't have more than 1 switch closed at a time. There are still labs which use equipment driven by Apple ]['s. In fact, (as of 1988) there are a few spectrophotometers which use Apples as controllers. But, of course, they don't tell their customers that! Jonathan A. Chandross Internet: jac@paul.rutgers.edu UUCP: rutgers!paul.rutgers.edu!jac