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The Apple II: The Machine That Started It All
Thomas Hormby writes "The first Apple II was sold on June 5, 1977. It was outfitted with a 1 mhz processor, 4 KB of RAM, a keyboard and a cassette interface. Despite the seemingly paltry specs, the machine made Apple, and bankrolled the LISA, Macintosh and LaserWriter. Besides building Apple, the machine revolutionized the entire microcomputer business, pulling it way from the hobbyist kits and closer to todays PC. Read about it at MLAgazine."
The PBS Triumph of the Nerds specials have additional information on the early years of the Personal Computer.
I only came here to do two things; kick some ass, and drink some beer...looks like we're almost out of beer.
TFA shows a picture of an Apple //e, not an Apple ][. To see the latter, look
here.
If you reply, do so only to what I explicitly wrote. If I didn't write it, don't assume or infer it.
Sorry- that wasn't the case. Commodity standard cassette recorders worked really well for storing Integer BASIC and machine language code and they used ordinary cassette tapes that were way way cheaper than floppies, particularly at that time.
It's psychosomatic. You need a lobotomy. I'll get a saw.
I worked in a computer shop selling computers at the time the apple II came on the scene. The brands around then were Imsai, cromenco, Sol, Northside, and even an altair if you wanted one. With the exception of the comodore pet, they all ran on 8080, 8085 or Z-80.
All had traditional power gobbling transfomer-rectifier-capacitor power supplies. If they had a bus it was an enornmous S-100 bus. None had memory mapped I/O or could interleave graphics and text. If they had disks, they were hard sectored disks. And most important of all none used Dynamic memory natively. You could buy dynamic memory cards as S-100 plug ins but they were not reliable.
Unlike the 8080/Z-80 the 6502 had a symmetric instruction clock cycle and all so there was a free cycle where memory woas gaurenteed not to be accessed every other cycle dependably. (not true of the 8080) This meant you could use that interval to refresh the dynamic ram. Thus one never had to insert wait states or have flaky thing happen when there was an irregular refresh rate. It simply worked.
But Wozniak and co, were even more clever. Why waste that clock refresh? since the duration was the same as the regular memory fecth time, they made it a full fetch. But what fetch that had to increment repetiviely over the upper 8 bits of address space would be useful? The video memory! so they backsided the video memory fetch on that.
Contrary to today having memory mapped video was better than having th e video memory on a graphics card. On most grpahic cards when the CPU was accessing the memory they video card could no and you saw glitches. thus video updates were usualy timed by the CPU to occur in thehorizonatal and veritcal re-trace blanking intervals. very clumsy and slow.
Apple used a switching power supply. the first I had ever seen. it was small, and took up no room. the imsai, altair, cromenco and northside computer were huge and half of them were the power supply. some of the capacitors in those were 8 inches tall and 3 inches in diameter. The switching powersupply made this thing a lighe weight "desktop" freindly unit. you could pick it up and easily move it.
It was partly the use of dynamic memory instead of static memory that made this possible. The power draw on static memory is enourmous. and the memory density on static memory was tiny. plus it was very expensive. it consumed most of the mother board. Today's computers would not be possible without it.
I assumed the apple II was a toy when I saw it's teeny tiny plug-in buss cards. until I looked at it's design. svelt memory mapped cards. all the address space decoding was done by the mother board so you didn't have to waste repetative logic on each card decoding it's own address. same with the power regulation. The switich power supply also gave lower ripple so less regulation was needed.
When apple came out with a disk it was the first reliable soft sectored floppy. I had sold lots of softsectored (8") floppies made by others and saw most of them come back too. Who wants an unrelaible storage system. The apple one worked. and soft secotring made it cheap since it had almost no added electorinics on board. It was all driven from software.
Then of course there was the choice of the 6502. it was a breath fo freshair compared to the 8080. It piplined the next instruction. it used relative jump extensively (calucalting an offset based on a register value not the hardwired instruction). It only had an accumulator and three registers. All the rest were memory mapped to the first 256 bytes of memory. So effectively it had enough registers you could really do something. the 8080 was hamstrung and register bound. and because of the pipelining the 6502 didn't lose any speed for the memory fetch using memory mapped registers.
However even then the MHZ myth was strong. people thought a 4Mhz intel must be faster than a 1Mhz 6502. It was not. nearly all the 8080 instructions were 3 to 5 clock cycles in length
Some drink at the fountain of knowledge. Others just gargle.
audio cassette tapes worked MOST of the time. But they were lower quality and more prone to damage. Also the data cassettes did not have a blank leader tape. thus you could start recording the moment you turned them on and not have to wait some period of time after a rewind to start recording. Finally when the recorder was controlled by the computer and not the human pushing buttons it could rewind and seek by itself. At that time audio grade readhead were not reccomended for fast forwarding the tape as they would be destroyed by wear. computer readheads were hardened.
but in simple fact for simple storage needs audio tapes and recorders sis work well. but there was a slightly higher risk of data loss.
Some drink at the fountain of knowledge. Others just gargle.
Cheap tapes worked fine for us TRS-80 folks too. The main problem with cheap tapes was dropouts. Since the TRS-80 had motor control, it would stop the tape player when it got an error, and you could usually see the bad spot on the tape that caused the dropout.
--
"Open source is good." - Steve Jobs
"Open source is evil." - Microsoft
I cut my computing teath on the apple //e. My friend
/// one of the best games ever.
had the ][+ with visicalc and 300 baud hayes modem.
The visicalc spread sheet was interesting because the left-right arrows became up-down when you pressed the space bar.
I remember
Beagle Bros software. Apple basic. Nibble magazine. 7 color hi res graphics (2 white , 2 black, purple, blue and orange). Ultima
The machine lives on in emulated form. How people got their 5.25 inch floppies into files I'll never now.
You could set the whole screen on solid color will a call command
if I remember correctly..
10 hgr
20 for i = 1 to 7
30 hcolor =i
40 hplot 0,0
50 call 62454
60 next i
super effects!
TI stopped making computers, but they damn sure survived. They do CPU fab like no one's business, including taking a lot of overflow orders from Intel.
"I'm guessing the parent was talking about NuBus and ADP, which is correct, they were not standard"
NuBus was most certainly a standard, with an IEEE number and all. It just was more common on minicomputers than micros.
Even ADB, Apple Desktop Bus, used to connect keyboards and mice, was adopted (sorta) by Sun for its keyboards.
requiring 3 - 5% or better tolerance is not acceptable. We had to hand-match Apple ][ drives back in '77 to ensure that the two drives could exchange data.
These were drives that took 200ms (yes, that's .2 seconds) per revolution. They had a trim-pot for speed adjustment and you had to put several turns on it to get the drive far enough out of spec to misread disks.
Hundreds of Disk II drives have passed through my possession, and I've never had to match their speeds to that level unless I was dealing specifically with a bitchy, temperamental nibble-count protected disk - and those were somewhat rare. Standard 16-sector format Apple II disks were phenomenally tolerant of speed variation. I respectfully submit that your memory likely exceeds your experience in this case.
As to "100%" reliable... it is possible to "accidentally" record a data pattern that duplicates the synchronization header. Just about the only system that this was possible on was the Apple ][.
The sector header (and there was one for EVERY sector, not one per track) consisted of 3-byte prologue (D5 AA 96) that used unique byte values that were not possible to generate using the standard 5&3 encoding scheme, followed by the track, sector and volume number 4&4 encoded into 6 bytes, followed by a checksum byte 4&4 encoded into two bytes, followed by a two-byte epilogue (DE AA) also using unique values not possible from the standard 5&3 encoding. If the checksum didn't validate those volume, track and sector values, the header was considered no good and ignored.
Yes, it is possible to "accidentally" record a pattern that would duplicate such a header. It's also possible (and probably just as likely) to throw a Scrabble set in the air and get Shakespeare. :)
However, saving the expense of (1) a proper floppy controller, (2) a proper video generator, (3) delegating everything to the 6502, did make the machine remarkably affordable.
Now this, I can agree with 110%. As a bonus, it also made the machine remarkably FLEXIBLE as well. There was very little - if anything - that the hardware prevented you from doing. The Apple II was a true "hacker's" machine, in the spirit of the original meaning of the word.
Just not remarkably dependable.
For unusual values of dependable, maybe. :) I have dozens of Apple //e's, Super Serial Cards, Disk II drives & controllers, all of which are 20+ years old and all of which are still as functional as the day they were built. How many other systems from that era are anything but dumpster fodder right now?
PS. U an looking for an Apple ][ DOS 3.3 boot disk. Email me if you can make me a copy.
I use ProDOS for the most part, especially since I only have a IIgs set up active at the moment. Not to mention DOS 3.3 support for hard drives is dismal at best. I'd have to dig for a bit to get you a DOS 3.3 disk. However, I do know people that could readily provide you one, and I'd be happy to get you set up.
Also, consider dropping by comp.sys.apple2 if talk of these older machines (and what they're still being actively used for today, like this incredibly cool project) is appealing to you.
"I feel that if a person can't communicate, the very least he can do is to shut up." -- Tom Lehrer
Wozniak spoke extensively about this period at Apple in a great interview at Gnomedex. It's available in high quality streaming audio on ITConversations: http://www.itconversations.com/shows/detail214.htm l