jecel

The original Smalltalk-72 focused on teaching children, but for Smalltalk-76 Alan Kay and Dan Ingalls wanted different things. Alan wanted to continue the kid focus while Dan argued that a language focused on advanced programmers could be used to implement a children's language on top of it. He was proven right decades later when EToys and then Scratch were implemented on top of Squeak Smalltalk, which closely followed Smalltalk-76.

This confusion frustrated me when I first read about Smalltalk in the August 1981 issue of Byte magazine. I couldn't figure it out and at that point I had learned several programming languages and none of them took me more than two hours to become reasonably fluent in. So I was having problems with a language that kids were using?!? Later on I found out about the differences between Smalltalk-72 and -80 and that the Byte articles explained things that made sense if you already knew them but didn't help you learn in the first place. All variations of Smalltalk have become my favorite way to program ever since.

Some prototype based languages use delegation instead of inheritance, so people assume that is the case for Self as well. The difference is subtle. But as you pointed out and Mario Wolczko said: "Self is like Smalltalk, only more so". There were also languages with neither inheritance nor delegation but that still included some scheme for sharing.

You are in luck: Alan Kay's original Smalltalk, also known as Smalltalk-72, doesn't have a syntax but instead allows you to define your own. Each class includes a single method that parses incoming messages however it wants.

The two problems with this were a lack of performance and the difficulty of understanding other people's code.

Dan Ingalls looked at the most popular styles people had created in Smalltalk-72 and defined a fixed syntax for Smalltalk-76 with the same flavor. This allowed him to "compile" -76 into bytecodes which would then be executed much faster by an interpreted virtual machine (and years later a JIT compiled one).

The analogy is putting grass everywhere in a new university campus and after a while seeing where the grass has been trampled and putting concrete sidewalks there.

For Smalltalk-80 they wanted people to be able to use it on their own computers and not only on the special Xerox PARC ones so the patched the syntax to use ASCII instead of their own character set. That made it uglier, in my opinion.

I can understand many people not liking the Smalltalk-80 syntax, but we do get some new people to the language every year and quite a few of them find the syntax one of the nicest features.

The first line of https://en.wikipedia.org/wiki/Logo_(programming_language) is "Logo is an educational programming language, designed in 1967 by Wally Feurzeig, Seymour Papert, and Cynthia Solomon." so you are correct but it is nice to mention his co-inventors. I agree about the book. I had to borrow it from a friend, read it quickly and give it back in 1983 so my memories of it are a bit fuzzy.

The simplest processors use one clock per instruction with a Harvard architecture. This allows their control unit to be a combinational circuit instead of a Finite State Machine (and depending on how your memories work you might even avoid having an instruction register).

Most one-instruction processors take multiple clocks and often need extra registers (for fetching 16 bit addresses from an 8 bit wide memory, for example) [1].

The four instruction MCPU [2] is not as bad to program as the one-instruction computers (it still needs 10 times as many instructions as a RISC-V, for example) while being very simple. Making it Harvard allows it to be slightly simpler and making it 16 bits allows it to run non trivial programs [3].

[1] https://github.com/jeceljr/SBN/blob/master/sbn.pdf

[2] https://github.com/cpldcpu/MCPU

[3] https://github.com/jeceljr/digitalCPUzoo/tree/main/MCPU

I think there were actually 68000 transistor positions. In the ROMs and PLAs not every potential transistor is populated but the missing ones were counted as well. But the number of actual transistors is only slightly smaller so it doesn't really matter.

One chip that could be used as a memory mapper for the 9900 (but wasn't in the TI99/4A) was the 74LS670, which was used in the IBM 5150 PC to allow the 8237 DMA chip to access more than 64KB (a limit that wasn't a problem when used in a 8080 system).

Note that RISC5 [1], a project created as a target for Wirth's Oberon compilers, is a different project from RISC-V [2], a project created at Berkeley which became what is currently the most popular open source ISA.

[1] https://riskfive.com/RISC5_overview.htm

[2] https://riscv.org/

It is funny that RISC-V International moved to Switzerland in 2020 so now both projects can be found in the same place.

We were stuck with 33MHz PCBs for a long time as people kept trying and failing to get 50MHz PCBs to work. Then Intel came out with the 486DX2 which allowed you to run a 50MHz processor with an external 25MHz bus (so a 25MHz PCB) and we started moving forward again, though we did eventually get PCBs to go much faster as well.

The Transputers (mentioned in other comments) had already decoupled the core speed from the bus speed and Chuck Moore got a patent for doing this in his second Forth processor[1], which patent trolls later used to extract money from Intel and others (a little of which went to Chuck and allowed him to design a few more generations of Forth processors).

[1] https://en.wikipedia.org/wiki/Ignite_(microprocessor)

The naming of processor sizes is the subject of debate. I call a "pure 8 bit processor" one that has 8 bits for both data and addresses. Like the Kenbak-1. But these are so rare and educational rather than practical that it is very reasonable to call hybrid 8 bit / 16 bit processors just "8 bit".

This use of sloppy terms shouldn't make us forget that they are using an address extension trick, just like all those 16 bit processors that wanted to go beyond 64KB (for byte addressed such as the PDP-11, Z8000 or 8086) or 128KB (for word addressed, like the Xerox Alto's modified Data General Nova model).

Michael J. Flynn, best known in the computing world for his taxonomy of parallel computing (SISD, SIMD, MISD and MIMD), passed away on December 24, 2025

Two years after this booklet, the CRT memory it describes was replaced by core memory (becoming the first computer to use that technology).

Most people are not aware that after the failure of the PS/2 attempt to control the PC market, IBM tried a third time using 7 patents it had for the PC AT (they didn't have any on the original PC or the XT). In the first half of the 1990s they went after the chipset makers (mostly in Japan at that time) and in the second half of the 1990s they went after the PC makers themselves all around the world. The would threaten to sue for all machines made up to that point unless they licensed not only the 7 AT patents (which would expire in 2001) but also a bunch of other unrelated patents that were much newer. As far as I know everybody signed the deal, which meant that IBM could make money without actually making any PCs themselves.

Here is a one hour talk Stewart gave at the 2016 VCF East (Vintage Computer Festival):

https://www.youtube.com/watch?v=Ncnje4DdRxE

He mentions that the first year it was a live program and they didn't have the resources to record them, so they are not available.

QNX was my operating system from 1985 to 1988. I also studied it in 2000 for a project that ended up getting cancelled.

Initially the actual implementation didn't match the conceptual framework, but by version 1.2 they had really cleaned things up.

One issue he mentioned is still true today in Brazil's universities: while in theory you can ask to transfer from one course to another, in practice you have to drop out of your current school and take the entrance exam for the other one. And then you waste a lot of time trying to get your grades for the courses you have already taken recognized as equivalent so you don't have to start from scratch.

For him to move from math to electrical engineering to physics in Brazil would mean going through this twice. This might make him take some 7 or 8 years to graduate.

I guess this inflexibility makes things easier for the administrators. They know they will have 25 students in the statistics class in 2028 and so know how many teachers to hire to handle that.

Actually, the 68000 had one full (all operations) 16 bit ALU and two more simple (add/subtract, so AU might be a better name) 16 bit ALUs so in the best case it could crunch 48 bits per clock cycle. The 8086 had one full 16 bit ALU and one simple 16 bit ALU (the ancestor of todays AGUs - address generator units).

The 68000 actually had both microcode and nanocode, so it was even further from hardwired control logic than the 8086. In terms of performance the 68000 was slightly faster than the 286 and way faster than the 8088 (I never used an 8086 machine).

They should say on this page that this project has ended. There are some spinoffs people interested in this can look into:

https://tinytapeout.com/

https://wafer.space/

https://chipfoundry.io/

The Indy 500 was actually part of the official Formula 1 calendar from 1950 to 1960, though the two series diverged after that.

Some Indy features (refueling, changing tires even if they didn't have a puncture, safety cars) got adopted by F1 through the 1980s, specially as F1 started to lose audience to the American series in the early 1990s.

Though a problem, as you point out, it still happened. The 6800 based SWTPC was followed by 6809 machines what need to have all their software reassembled.

On the other side of the cpu wars, all those 8080 machines moving on the Z80s got to keep all their binary software, which happened again for IBM PCs and clones as those evolved.

https://en.wikipedia.org/wiki/SWTPC_6800

Thank you for correcting me. I don't know where I heard the story I mentioned.

My own memory of the events (which might be very wrong) was that a new vice-president of IBM semiconductors decided to drop bulk CMOS and focus exclusively on SOI (Silicon On Insulator). That suddenly left Transmeta without chips to sell. They had to scramble to find a new supplier and design their next generation processor for it (since the Crusoe wasn't portable to any other fabs). They were able to launch their Efficeon on TSMC 130nm (with a later version on Fujitsu 90nm) but the gap in supply was far worse for a startup than it would have been for a big company.

The VM in Slang had been previously published as part of the "blue book" (now that is what I call open source!) some 14 years before, and as the paper you linked to mentioned, Mario Wolczko at the University of Manchester had typed it in so it was available in machine readable form.

They did drop the object memory part completely and designed a new one from scratch.

Previously people had manually translated the VM from Slang to Pascal or C (I did so myself in 1986) but for this project they wrote a tool for that (in Smalltalk, of course).

Here is another copy of the "Back to the Future" paper:

http://www.mirandabanda.org/files/Papers/BttF.html

If we label the combinations of the seen and scanned bits as:

00: white

10: gray

11: black

then we cam describe it as a very cool variation of the tri-color gc algorithm.

https://en.wikipedia.org/wiki/Tracing_garbage_collection#Tri...

> Finally, a programing job that AI won't be able to replace.

Well, at the recent VCF (vintage computer festival) Midwest they showed a robot using the Altair's front panel to toggle in a game:

https://techav.net/post/796938975198707712

Exactly, but the text has the same instruction sequence twice and the parent correctly indicated that the first copy should have used "lui" to illustrate the problem you mentioned and the second copy does use "auipc" to illustrate the fix you mentioned.

The problem with Self in the 1990s wasn't the lack of sources (I just checked the 1994 Self 4.0 sources and the license looks like the typical BSD one) but the fact that the binaries only ran on Sparc workstations and not the computers people actually had. I might as well post the whole text of the license:

# Sun-$Revision: 21.2 $

Copyright 1995 Sun Microsystems, Inc. and Stanford University.

All Rights Reserved. RESTRICTED RIGHTS LEGEND: Use, duplication, or disclosure by the government is subject to restrictions as set forth in subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software Clause at DFARS 252.227-7013 (Oct. 1988) and FAR 52.227-19(c) (June 1987).

Sun Microsystems, Inc. 2550 Garcia Avenue Mountain View, CA 94043 USA

LICENSE:

You may use the software internally, modify it, make copies and distribute the software to third parties, including redistribution for profit, provided each copy of the software you make contains the copyright notice set forth above, the disclaimer below, and the authorship attribution below.

DISCLAIMER:

Sun Microsystems, Inc. makes no representations about the suitability of this software for any purpose. It is provided to you "AS IS", without express or implied warranties of any kind. Sun Microsystems, Inc. disclaims all implied warranties of merchantability, fitness for a particular purpose and non-infringement of third party rights. Sun Microsystems, Inc.'s liability for claims relating to the software shall be limited to the amount, if any of the fees paid by you for the software. In no event will Sun Microsystems, Inc. be liable for any special, indirect, incidental, consequential or punitive damages in connection with or arising out of this license (including loss of profits, use, data, or other economic advantage), however it arises, whether for breach of warranty or in tort, even if Sun Microsystems, Inc. has been advised of the possibility of such damage.

AUTHORSHIP:

This software has been derived from the Self system, which resulted from the combined efforts of:

Bay-Wei Chang, Craig Chambers, David Ungar, Elgin Lee, John Maloney, Lars Bak, Mario Wolczko, Ole Agesen, Ole Lehrmann Madsen, Randall B. Smith, and Urs Hoelzle.

The early microcomputer market had three kinds of companies:

- those with organic growth, where the sales of products financed the development of new products: MITS, IMSAI, Sphere, Ohio Scientific, SWTPC, Cromemco, Processor Technology, etc

- those that were part of a larger company: Radio Shack, Commodore, Texas Instruments and Atari-Warner

- those that were financed by venture capital: Apple

In retrospect, the companies in the first group were doomed to not become an Apple. Later on we got many more venture capital based computer companies, with Compaq among the most famous.

In the case of Sphere it had many more problems than just how it was financed. They got an early reputation for not delivering at all or shipping non working products.

What was special about Sphere was that from a technical point of view it was a generation ahead of the competition: with a built-in screen it was more like a Commodore Pet or a Radio Shack TRS-80 from 1977 than like the boxes with LEDs and toggle switches from its peers in 1975.