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posted by
martyb
on Sunday October 07 2018, @01:14PM
from the have-you-ever-programmed-a-6502? dept.
from the have-you-ever-programmed-a-6502? dept.
Adafruit visited the history of the LOGO "turtle graphics" language not long ago.
Now on Twitter, folks have found the source code for the LOGO program used on Apple II computers. Source on GitHub.
It turns out that the program was written on a DEC PDP-10 minicomputer running the Incompatible Timesharing System (ITS).
I'd take it that the code is in 6502 assembly and the program works the whole Apple II memory map for functionality. Did ITS have a 6502 cross-compiler or did the MIDAS program have separate target environments?
Very interesting programming archaeology – see the source code yourself along with the full PDP-10 ITS image still maintained today.
-- submitted from IRC
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The Apple II Source Code for the LOGO Language Found
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But it does move!
-- Galileo Galilei
(Score: 2) by Arik on Sunday October 07 2018, @01:56PM (3 children)
And even with two halves spoken for, there were somehow breaks and lunch left over. Those were mostly spent listening to music by the fence.
I had "Wierd Al Yankovic" and "Speaking in Tongues" on cassette.
Good times.
If laughter is the best medicine, who are the best doctors?
(Score: 3) by driverless on Monday October 08 2018, @05:10AM (2 children)
Then it was quiet again. My attorney had taken his shirt off and was pouring beer on his chest, to facilitate the tanning process. “What the hell are you yelling about?” he muttered, staring up at the sun with his eyes closed and covered with wraparound Spanish sunglasses. “Never mind,” I said. “It’s your turn to drive.” I hit the brakes and aimed the Great Red Shark toward the shoulder of the highway. No point mentioning those bats, I thought. The poor bastard will see them soon enough.
(Score: 2) by captain normal on Monday October 08 2018, @05:31AM
Hey!! Leave Hunter Thompson out of this. He's innocent I swear.
Everyone is entitled to his own opinion, but not to his own facts"- --Daniel Patrick Moynihan--
(Score: 0) by Anonymous Coward on Monday October 08 2018, @04:10PM
Parent was not spam, you ignorant fucks. Go read a book.
(Score: 4, Funny) by Hyperturtle on Sunday October 07 2018, @03:23PM (2 children)
"Now on Twitter, folks have found the source code for the LOGO program used on Apple II computers"
Twitter didn't even exist back then. But I guess 128 characters per line is a reasonable limitation for a confused turtle trying to make graphics with a low bandwidth connection. I guess it IS slow and linear or you get really confused going from point to point... yet often enough, twitter has no real point. Maybe it was a freeform type of logo, where the turtle decides where to go based on retweets? Even thought there may be no point, the turtle could be serious about art is for art's sake.
Alright so Let me try to get this straight now that I've confused myself: Based on the summary, the turtle graphics source code was found on Twitter and had been written on a DEC PDP-10 that proved to be incompatible with everything, even with multitasking. I wonder if it also was funded via American Express cash advances. Early Apple funding was dicey like that. And as to American Express: no one accepts those cards, no one that poor programmers shop anyway, so it'd make sense it was incompatibly time shared on a different platform on a public forum for a defunct system that can be emulated in an emulator. Next we'll find they flipped the turtle over onto his back and stole his floppy disks as he struggled to flip himself over since his turtles are not productively double-sided like that.
How much storage is there when the turtles go all the way down, anyway? And will the compiler error out due to the turtle going out of bounds if there is no lower boundary?
(Also, I know I am wrong--everyone knows turtles are like double-sided discs with auto-flip technology built right into their enclosures, and they have lots of storage capacity intended for rugged applications; turtles don't ever skip. Twitter is not nearly as durable. But I only read the summary, and I took it literally! We need figuratively enabled editors to help curate the ATK robot's posts.)
(Score: 4, Touché) by Bot on Sunday October 07 2018, @04:42PM
>But I only read the summary, and I took it literally!
You are supposed to base your comments exclusively on the title, reading TFS or TFA is akin to cheating.
Account abandoned.
(Score: 0) by Anonymous Coward on Monday October 08 2018, @06:24AM
"...funded via American Express cash advances. Early Apple funding was dicey like that."
Actually early Apple funding was mainly a guy with wild red hair and a fu-manchu from Chemeketa Park (supposedly named Jim) who would show up at the Good Earth Cafe and Organic Food Store in Los Gatos whenever the Homegrown Computer Club would meet there. He would come in with grocery bags of cash, Fairchild op-amps and Panama red. He would hand these over to Woz and the party was on.
(Score: 4, Interesting) by Azuma Hazuki on Sunday October 07 2018, @03:27PM (4 children)
Back in kindergarten there were some Apple IIe machines in one of the rooms. First time I remember actually using a computer, rather than just banging at the keyboard on my father's when he brought me in to work one morning, was that one. And it was running LOGO. And I was one of those wise-ass kindergarteners who could handle 4-digit letters, and asked the turtle to walk 5,000 steps to see what happened. What happened was a unholy buzzing fan noise and then a field full of stripes, more or less.
I am "that girl" your mother warned you about...
(Score: 2) by requerdanos on Sunday October 07 2018, @05:36PM (1 child)
I almost hesitate to ask what language and alphabet you were learning that had multi-digit letters.
(Score: 2) by Azuma Hazuki on Sunday October 07 2018, @06:06PM
The one I remember before morning coffee, sorry @_@
I am "that girl" your mother warned you about...
(Score: 3, Interesting) by canopic jug on Monday October 08 2018, @07:18AM (1 child)
Clever.
Moving a "turtle" around on the screen was all I ever saw it do, though I only took a quick look at it and had no one to show it to me. So I dismissed Logo as irrelevant because you could do way more with 6502 assembly if you had lots and lots of time and the skill. If you had less time and less skill then Applesoft BASIC had functions like HPLOT() and really, really slow gimmicks like Shape Tables. So I never saw the point of Logo but perhaps I missed something. What was Logo intended for and what could it do besides the turtle thing?
Money is not free speech. Elections should not be auctions.
(Score: 0) by Anonymous Coward on Monday October 08 2018, @12:53PM
From Wikipedia: [wikipedia.org]
(Score: 4, Informative) by requerdanos on Sunday October 07 2018, @05:34PM (16 children)
In the below quoted snippets, emphasis has been added by a secret recipe.
First: Saying that the long-lost code has been found "on twitter" or that the folks are based "on twitter" is like saying that a book was found "in the library" or saying "the library has found" when you mean incidental random patrons. Put another way, saying "someone found (item) on (twitter)" or "the folks on twitter found (item)" is a linguistic equivalent of saying "I do not understand folks, twitter, looking, searching, nor finding, nor how any of those things work, and should shut my pie hole."
Second: Apple II computers did not work like that. They were blank slates that may or may not have had integer and/or other BASIC in ROM, and who could boot an entirely different environment from a diskette by, usually, the somewhat less than intuitive command "PR#3" ("give control to the peripheral in slot number three, please").
As such, each diskette booted its own island environment quite separate from "the Apple II" itself as such.
This means that if you wanted to run "Logo", you had to find "Logo" on a diskette that would boot. And there were several. For example, in addition to LSCI's "Apple Logo" and "Apple Logo Writer" [wikipedia.org], the Apple II also had offerings like Terrapin Logo [terrapinlogo.com].
This means that a statement such as "the LOGO program used on Apple II computers" is meaningless, on the order of "That idiot on twitter." It treats many different things as if they were all one, or as if there were only one of each rather than each being an instance of its class. Put another way, it's a way to say "I do not understand the Apple II series, Logo, singular, collective, plural, nor how any of those things work, and should shut my pie hole."
I will now lead by example and shut my pie hole.
(Score: 4, Interesting) by bzipitidoo on Sunday October 07 2018, @06:08PM (9 children)
Too late, you spewed Apple pie all over everyone's mom.
It's been a while since I last used an Apple II, but I used to know them pretty well.
It was customary to place the disk controller in slot 6, and 256 byte bootstrap code there would be automatically executed when the machine was powered on or reset, no need for "PR#3". Most disks had DOS on the first few tracks, and would boot. For most applications and games, it was simply more convenient to have DOS on each disk, rather than use a separate boot disk. Why not? The computer had only 48k or 64k RAM, and the disk would hold more than twice that.
The only surprising thing is that the LOGO source code was ever lost. But then, seems a lot of code from those days was never preserved.
(Score: 1, Redundant) by requerdanos on Sunday October 07 2018, @07:12PM (1 child)
Some would have been horrified at the idea of the disk controller being placed where it would fire off without a command from the super-geek power user in control. It certainly never occurred to me to put it there. (What "slot" was it in on an Apple IIc?) Though now in hindsight I see how that might have been pretty useful.
That said, I will amend my interpretation of TFS as follows:
"Some unspecified person or persons found, in some unspecified place or places, some source code, for some unspecified LOGO interpreter, from some unspecified vendor or author, that could potentially have automatically booted on those Apple II computers which were so configured."
(Score: 1, Informative) by Anonymous Coward on Sunday October 07 2018, @10:32PM
There you exposed yourself, a phony windbag.
(Score: 2) by Rich on Sunday October 07 2018, @11:04PM (5 children)
The Disk II interface card "customarily" resides in slot 6. I/O addresses are at $C0E0-C0EF ($C080+$10*slot). $C0E8/9=motor, C0EA/B=drive, C0EC:read latch. C0E0..C0E7: phases 0..3 of the stepper. Forget to turn the phases off (or worse, turn on all phases), and you're eventually in for a bit soldering to swap the ULN2003 on the analog board. PROM address is at $C600 (again, $C000+$100*slot). Jumping to $C600 initiates the boot. There are early non-autostart ROMs, where you had to manually boot. Either *C600G from the monitor, or PR#6 (or IN#6) from Integer Basic. The PR/IN commands redirect the COUT routine at $FDED to the slot PROM (the direct video output is at $FDF0). So it's a slight trick to redirect the character output to floppy boot code. Apple II+ and on have autostart ROMs, which search for the disk controller after cold reset (which is detected by a memory flag, warm reset will (usually) drop to BASIC).
Slot 3 customarily took the 80-column card, which was activated with "PR#3" (putting the redirection logic to proper use). There is also an extended PROM area from $C800..$CFFF than can mapped in by a card (which primarily is used by the Videx-style 80-column cards. And don't forget to deactivate through $CFFF, or there will be bus conflicts).
Now you know, even if you didn't want to. Everything out of my head, and it's been a few years, so no guarantees on correctness, but i'm rather confident ;)
(Score: 3, Interesting) by bzipitidoo on Monday October 08 2018, @01:39AM (4 children)
Heh, I knew about the phases for the stepper motor, but didn't know they could all be left on and fry a chip. I knew the Commodore 64's disk drive could be instructed to damage itself-- think it could be made to bump the read head against the side of the case or some internal component, thus knocking it out of alignment, and heard there was at least one game that allegedly used this to punish pirates if it detected it was a pirated copy.
One caveat about your masterful knowledge: the language card. There was a 16k expansion card, called a "language card", that could be added to turn a 48k machine into a 64k machine. This extra 16k used the same high memory addresses as the ROM, which held the BASIC programming language, hence why it was called the language card as it could be used to "replace" the language, and was often used to run the older Integer BASIC on Apples that came with the newer floating point Applesoft BASIC. There was a memory location that would toggle between the ROM and the card's RAM. I don't recall for certain, but think it could mask even the other expansion cards so that C600G could be a call to anything if the machine was reading the language card rather than the ROM.
Also very useful for breaking copy protection-- used the language card to break Ultima IV. Boot trace to the point that Ultima IV's custom, copy protected DOS was loaded, putting a break just after letting it execute their cutesy little XOR code deobfuscation routine, make it read its boot disk, then toggle the language card and use standard Apple DOS to write the data back out to a different floppy disk that had been formatted with the standard format. Didn't have to modify the code in the slightest, as the Ultima IV DOS was designed to read standard format, to handle the rest of the disks, and didn't bat an eye at the boot disk also being in standard format. Once that was done, I started hacking on the game. Changed the graphics to make it more colorful, not have so much black background. Even optimized the tile drawing routine to make it a little faster.
Lot of low hanging fruit in Apple II games, particularly the ones that used BASIC. Like, there was this Dark Forest game (a computer adaptation of an old Avalon Hill game, Wizard's Quest) that used the BASIC line drawing routines to draw horizontal blue lines on the top row of text, to erase text messages. Of course it was incredibly slow-- could see the individual lines being drawn. I replaced that with a lightning fast assembly language routine. Then, Dark Forest had a bug in which it would sometimes incorrectly compute the number of men you received for reinforcements. I corrected it, and made it much faster. Another terrible one was a very basic galactic conquest kind of game, which needed 30 seconds to generate a galaxy thanks to the idiotic algorithm the author chose to check that no two planets ended up in the same location. The improved method took about 1 second, if that. Earth Orbit Stations has a bug deep in the game which I managed to fix once by accident, but I never could figure out what I did, so it stayed broken.
(Score: 2) by Rich on Monday October 08 2018, @01:56PM (3 children)
Mine had two switches soldered in, a toggle to disable the software switching of the card (so the interrupt vectors were immutable), and a pushbutton for NMI. Hello "Snapshot"! Those were the days. :) Eventually I got a Saturn 128K card, but my mind is blurry whether i used to swap those two (which would have been extra effort, because the classic language card tapped into one of the 4116 sockets, and I don't remember this particular socket wearing out).
I wrote all the embedded code for a Woz machine clone in a standalone RS-232 connected "smart" floppy drive that was solely made to read machine knitting-patterns (which apparently was a total Apple II domain) into newer Silicon Graphics workstations. I guess that's why these particular details stuck so well (besides helping out the occasional game with a ..er.. compatibility-improved RWTS...). A friend then did the DOS3.3 file system utilities for the DOS and Unix machines.
Recently, I also started wearing a long grey beard.
(Score: 2) by bzipitidoo on Monday October 08 2018, @06:18PM (2 children)
Cool. I didn't have that hardware mod, but I did have a toggle switch to set the floppy disk write protection any way I wanted (on, off, or detect the notch), and a rotary pot from an old radio to control the volume. Saved a lot of bother punching notches for the reverse sides of floppies. I also used, as I recall, a 130 ohm resistor to touch 2 pins in any expansion slot-- maybe it was pin 29 and 32-- and this generated an interrupt, breaking into any BASIC program. Never got around to wiring that resistor in, in a more permanent way, with a push button momentary switch.
I also have a few gray hairs in my beard :p.
(Score: 2) by Rich on Monday October 08 2018, @07:17PM
If you ever get to central Germany and want to discuss further details (and lament how the world's come down since), the beer's on me. ;)
(Score: 0) by Anonymous Coward on Monday October 08 2018, @07:26PM
Beard was, seemingly, mandatory if you worked at computer shops that sold Apple computers (although they typically also sold kaypro and other garbage game machines). The new-fangled hipsters has not a clue.
(Score: 2) by dry on Monday October 08 2018, @02:06AM
IIRC, the original Apple II didn't automatically boot, not even sure if it came up in basic or in the monitor and the usual was typing in 6p or something similar to boot. Adding the language card (original with Applesoft in ROM) may have updated it to boot on power up.
(Score: 2) by sjames on Sunday October 07 2018, @07:35PM (1 child)
That's a lot of words to say "I want to disagree so bad I'm willing to contort common understanding of the language to do it.
In the same spirit, why exactly do you enjoy spanking yourself with rosemary bushes at midnight?
(Score: 2) by requerdanos on Sunday October 07 2018, @08:37PM
Meeting the ridiculous with the hyper-ridiculous is just another free service I offer (people also got tired of the free sarcasm).
Out of curiosity, are you making a particular argument against rosemary, or just asking?
(Score: 3, Insightful) by SomeGuy on Sunday October 07 2018, @07:48PM (3 children)
You forget, people get paid for mentioning Twitter(R)(TM). Don't you watch the TV news? Every major event is announced on Twitter(R)(TM) and they are proud to provide the detail of precisely and exactly where it was announced - on Twitter(R)(TM)! Every major scandal revolves around saying something baaad on Twitter(R)(TM). People go to jail for making Terroristic Threats on Twitter(R)(TM). If you mention something on your own personal web site, it isn't official - you have to say it Twitter(R)(TM)! The fucking president of the United States of Fucking America Tweets everything he does on fucking Twitter(R)(TM). IF YOU DON'T USE TWITTER(R)(TM) THEN YOU ARE NO ONE!
And don't forget to download our free news app/malware and follow us on Twitter(R)(TM)!
Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)! Twitter(R)(TM)!
(Score: 2) by requerdanos on Sunday October 07 2018, @09:12PM (2 children)
Actually, like many "cord-cutters", I mostly don't watch the TV news. I guess my non-understanding of the Twitter-apropos-of-nothing gave it away, huh?
Is it like "I'm the secretary of state, brought to you by Carl's Jr" [freworld.info]?
(Score: 0) by Anonymous Coward on Monday October 08 2018, @06:03AM (1 child)
What do you mean "cord cutters"? You can get the news off the air. Don't need cable, coax or copper to get TV. Do you get your news off the interwebby and only look at 4chan?
(Score: 0) by Anonymous Coward on Monday October 08 2018, @01:01PM
And how do you get the news from the air into your TV? Right, through an antenna. And how do you connect that antenna to your TV?
(Score: 2) by epitaxial on Sunday October 07 2018, @08:51PM (2 children)
A PDP-10 seems like it would be ancient by the time the Apple II was released. Wonder why that system was used?
(Score: 0) by Anonymous Coward on Sunday October 07 2018, @09:44PM
LOGO for APPLE2 descended from PDP LOGO most likely.
Also likely is that the APPLE2 wasn't released yet when the project to port LOGO to it started.
It was probably announced as some spec set in order to get early ports.
The hobbyst community was different back then and apple was part of the hobby hacking movement.
If Woz was slipping out spec sheets to user's groups and bulletin boards and saying "this is coming, get a port ready", lots of people would do it just for the challenge.
This was the days before open source, but the ethos was stronger IMHO.
(Score: 0) by Anonymous Coward on Monday October 08 2018, @12:16AM
In the late-70s I worked briefly on the Terrapin Turtle, a "robot" peripheral that connected to Apple II by a cable and could draw with a pen (like a plotter -- pen_down and pen_up commands) on any surface that would accept the ink. Along the way I got to know many people in the Logo community, which was the brainchild of Seymour Papert and others at MIT.
As well as the programming language, this community also did educational experimentation in a variety of different schools (low and high income areas, for example). They were very successful in getting elementary kids to program, sometimes working collaboratively--YouTube has videos, very inspirational watching kids solve programming problems. Many of these folks are still around, wouldn't surprise me at all if several people hung onto copies of the source.
While I don't know the exact details, the reason to use the PDP-10 at the MIT AI Lab, which ran ITS (Incompatible Time Sharing) was almost certainly this: ITS was written by some of the best hackers, for their own use and it was by far the best/fastest software development environment of its era. This is where RMS hung out while he was an undergrad at Harvard, there is a good section on the AI Lab in https://archive.org/details/faif-2.0/page/n0 [archive.org] (this link was posted here on SN recently, I'm having fun (re)reading this updated version).
Since Logo is effectively interpreted Lisp (with different syntax), and since the PDP-10 had excellent Lisp support (all written in-house, before commercialization by Symbolics and Lisp Machine Inc), it probably wasn't all that hard.
As well as various different versions of Logo for the Apple II, and the Turtle robot peripheral, there was also a memory card produced that doubled the available memory for use with larger Logo programs--adding 64K bytes to the 64K in a maxed out Apple II. I had one and it came with instructions for how to use the extra memory with other software as well, although I don't think there was much support. There was also Logo for other home computers c.1980, for sure it was ported to TI and Atari computers.
Logo short history - http://el.media.mit.edu/logo-foundation/what_is_logo/history.html [mit.edu]
Page has links to other sections on the language and the educational activities as well.
(Score: 0) by Anonymous Coward on Monday October 08 2018, @12:40AM
Apple II Logo may have been one of the first microcomputer ports, but there have been many. Here's one attempt at a list:
https://web.archive.org/web/20090306084150/http://elica.net:80/download/papers/LogoTreeProject.pdf [archive.org]
with 196(!!) entries.
(Score: 0) by Anonymous Coward on Monday October 08 2018, @07:56PM
I recall programming Apple IIe computers in LOGO in early high school.
It was such a powerful experience because the language was high level and new commands you defined stayed resident in memory to build upon using newer commands. Very interactive. The one drawback was knowing when to quote a variable and when not to. It seemed a little arbitrary and error prone. Later in life, I found out that LISP which inspired LOGO has the same problem.