Archive for the 'Just For Fun' Category

June 27th, 2015 ~ by admin

The 16-bit Transistor level MegaProcessor

16-bit MegaProcessor ALU

16-bit MegaProcessor ALU

James Newman in Cambridge (UK) is16-bit discrete Processor Design called the Megaprocessor (there is nothing micro about it).  Not a VLSI version either, a 16-bit processor built of discrete transistors, hand wired, hand soldered, with debugging provided by…3500 LEDs.  He admits perhaps things got a bit out of hand when a co-worker remarked that it would be helpful if a signal had an LED on it, thus providing the motivation to go out and build a complete 16-bit processor.

James estimates that the design (he is still building it) will take 14,000 discrete transistors, 3,500 of which are actually to drive the LEDs.  ROM and RAM (256 bytes each, assuming he doesn’t get carpal tunnel from soldering it all) will be an extra 16,000+.

An original Intel 8086 used 29,000 transistors, and was a similar 8/16 bit architecture.  The Novix NC4016 stack processor, also 16-bits, was a very clean design using only 16,000 transistors.  HPs original BPC 16-bit processor from 1975 was 6,000, so James design is certainly inline with expectations (though his sanity maybe in question).

While this seems like a crazy amount of work (it is), This is how the first transistor computers were made.  The original DEC PDP-1 from 1959, used 2,700 discrete transistors, and was an 8-bit design.  The Apollo Guidance computer from 1966 was a 16-bit design (using IC’s with 3 transistors each, so a bit easier construction) used 12,300.

So while James’ design may be a bit over the top, it provides a good look back at where we have come.  Today chips can have well over a billion transistors on a die smaller then a fingernail.

Posted in:
Just For Fun

March 29th, 2015 ~ by admin

I Just Poured Water on my Scanner….

Chip that come into the museum are all scanned on a Canon 5600F flatbed scanner.  It has a good (there is some better though) depth of field, and its fast.  Typically chips are scanned at 300dpi, or for small ones (or ones that have a die visible) 600dpi.  This keep the file sizes reasonable, yet still allows them to be studied in good detail on as well our records.

There are on occasion chips that are VERY hard to scan, either the markings are very small, or very shallow.  This is becoming common on more modern chips, for one the chips themselves are smaller, and second, they are most often laser marked, and there isn’t enough thickness in the package (or die on some) for the Grand Canyon engraving of the 80’s.

1200 dpi dry scan

1200 dpi dry scan


This is a Intel QG80331M500 IO Processor made by Intel in 2007.  It is the replacement for the 80960 based I/O processors, using instead a 500 MHz XScale ARM Processor core.  This scan was done at 1200 dpi, the part number is visible, barely, but the S-spec and FPO (lot code) are not.  The markings are laser etched directly onto the surface of the silicon die.  This is fairly common on this type of chip (as well as most all of Intel chipsets).  How do we improve upon this?  Bumping the resolution to 2400dpi just makes a bigger blurry picture (with more noise).  What we need is better resolution, at where the scanner works best (less noise at 1200 dpi scan).

Thankfully we can use a ‘technology’ that is very much similar to how modern processors themselves are now made.  Dumping water on the scanner, also known as immersion scanning.

Read More »

December 20th, 2014 ~ by admin

Monsanto: Bringers of the Light

Monsanto MCT2 - LED Based Opto-coupler

Monsanto MCT2 – LED Based Opto-coupler

This little chip, dated from 1973, is part of the history of what we are surrounded by, LEDs.  And they have an unlikely and somewhat surprising beginning.  The MCT2 is an opto-coupler, basically an LED and a phototransistor in a single package, used for isolating digital signals.  The important portion here is the LED.  LEDs are in nearly every electronic product these days, and this Christmas season we see many Christmas lights that are now LED based.  THey are more efficient, and much longer lasting.  Certainly the eco-friendly choice for lighting.  And they have their roots in a company that does not always elicit an eco-friendly discussion.

That would be Monsanto.

That big ‘M’ on the package is for Monsanto, who from 1968-1979 was the leading supplier of LEDs and opto-electronics.  In 1968 there were exactly 2 companies who made visible light LEDs (red), HP and Monsanto, and HP used materials supplied by Monsanto to make theirs.

LED Christmas Lights

Read More »

October 15th, 2014 ~ by admin

Has the FDIV bug met its match? Enter the Intel FSIN bug

Intel A80501-60 SX753 - Early 1993 containing the FDIV bug

Intel A80501-60 SX753 – Early 1993 containing the FDIV bug

In 1994 Intel had a bit of an issue.  The newly released Pentium processor, replacement for the now 5 year old i486 had a bit of a problem, it couldn’t properly compute floating point division in some cases.  The FDIV instructions on the Pentium used a lookup table (Programmable Logic Array) to speed calculation.  This PLA had 1066 entries, which were mostly correct except 5 out of the 1066 did not get written to the PLA due to a programming error, so any calculation that hit one of those 5 cells, would result in an erroneous result.  A fairly significant error but not at all uncommon, bugs in processors are fairly common.  They are found, documented as errata, and if serious enough, and practical, fixed in the next silicon revision.

What made the FDIV infamous was, in the terms of the 21st century, it went viral.  The media, who really had little understanding of such things, caught wind and reported it as if it was the end of computing.  Intel was forced to enact a lifetime replacement program for effected chips.  Now the FDIV bug is the stuff of computer history, a lesson in bad PR more then bad silicon.

Current Intel processors also suffer from bad math, though in this case its the FSIN (and FCOS) instructions.  these instructions calculate the sine of float point numbers.  The big problem here is Intel’s documentation says the instruction is nearly perfect over a VERY wide range of inputs.  It turns out, according to extensive research by Bruce Dawson, of Google, to be very inaccurate, and not just for a limited set of inputs.

Interestingly the root of the cause is another look-up table, in this case the hard coded value of pi, which Intel, for whatever reason, limited to just 66-bits. a value much too inaccurate for an 80-bit FPU.

August 13th, 2014 ~ by admin

What’s Missing?

Four-Phase Systems: 1969-1981

Four-Phase Systems: 1969-1981 (click to enlarge

What’s Missing from this Four-Phase Systems family portrait?  Hopefully the lost member arrives this week.  Anyone remember Four-Phase?

Posted in:
Just For Fun

September 14th, 2013 ~ by admin

Intel 8 Inch Flexible Disk – 1.2MB of Data

Intel 8" Floppy Disks (10 Pack) - Minimalist Packaging ahead of its time.

Intel 8″ Floppy Disks (10 Pack) – Minimalist Packaging ahead of its time. 1.2MB

The original floppy disk was introduced by IBM in 1971 as a way to serve updated microcode to their clients mainframes.  Each disk could hold around 80KB.  By 1977 the DSDD (Double Sided, Double Density) 8 Inch disk was released which held 1.2MB of data.  They were officially known as a ‘Flexible Disk’ but floppy disk rapidly became what people referred to them as.  Intel marketed and sold them as well as many other manufacturers.  Intel accepted code for MaskROM based processors, on 8 inch floppy, tape, and a variety of other formats in the 1970’s.  Certainly 1.2MB was a great plenty of storage for the 1-8KB of ROM most microcontrollers and MaskROMs supported in that era.

In 1978 a ‘consumer’ version of the floppy was released, in a more friendly size, but lower capacity. This was the 360KB 5.25″ disk that was eventually made famous by the IBM PC, TRS-80, Apple. and about every other computer of the late 1970’s and early 1980’s. 8 Inch Flexible Disk

Floppy disks continued to evolve into the late 1990’s trying to compete with the CD-ROM, with capacities eventually hitting 240MB with the LS-240 Laser Servo drive.  In the early 21st century companies, largely led by Apple, began to delete the floppy from their computer line up, causing quite a stir.  However, users quickly realized that contrary to popular belief, the floppy really wasn’t used much.   Ultimately the use of the floppy, and the CD have been replaced with the USB Flash Drive, and in many ways, cloud computing.

Posted in:
Just For Fun

May 25th, 2013 ~ by admin

Another Apple 1 Computer, Another $671,400

Apple 1 computers, one of the first personal computers, were introduced in 1976. Now 37 years old they are setting records for auction sales.  In September 2010 one fetched over $20,000 on eBay.  A few months later one with the original box and papers cleared $200,000.  And this week an auction house in Germany sold one for 516,000 Euros (around $670,000 depending on the exchange rate).  Apparently a refurbished and now working model. this is one of the highest prices ever for a vintage computer.

Who knows, in 30 years the original iPhone 2G may set records for sales, but considering the number built, who knows how many will be around in 2040, or how many will have the original box.

Posted in:
Just For Fun

April 16th, 2013 ~ by admin

Project Unity: 15 Game Consoles and 18 Processors

projectunityMaster Modder Bacteria recently completed ‘Unity’ a single cabinet integrating 15 classic consoles, and capable of playing games from 18 different systems (sme consoles can run more then one type of game.  It an impressive feat especially considering he managed to make it work off a single controller, and a single video/audio output.  A custom 15-position switch tops off the console.

The consoles range from a Intellivision and its oddball CP1610 General Instruments (based on the PDP-11) processor, to the wildly successful 299MHz Sony PS2.  Below you can see the variety of systems, and the processors (this IS the CPU Shack after all) that run them.

Console Processor(s)
Amstrad GX4000 Zilog Z-80 4MHz
Atari 7800 MOS 6502 1.79MHz
Colecovision NEC 780C-1 (Zilog Z-80) 3.58MHz
Mattel Intellivision GI CP1610 894KHz or 1MHz
NEC TurboGrafx 16 Hudson Soft HuC6280 (65C02 based) 7.16MHz
NeoGeo MVS Motorola MC68000 12MHz + Zilog Z-80 4MHz
Nintendo NES Ricoh 2A03 (6502 Core) 1.79 MHz
Super Nintendo Ricoh 5A22 (GTEu 68C816 core) 3.58 MHz
Nintendo 64 NEC VR4300 (MIPS) 93.75 MHz
Nintendo Gamecube IBM PowerPC “Gekko” 486 MHz
Sega Master System Zilog Z-80 3.58 MHz
Sega MegaDrive (Genesis) Motorola MC68HC000 7.67MHz + Zilog Z-80 3.58 MHZ
Sega Saturn Hitachi SH-2 32-bit RISC 28.6 MHz
Sega Dreamcast Hitachi SH-4 RISC 200 MHz
Sony Playstation 2 Emotion Engine (MIPS based) 299MHz

As you can see a few processors are common. Five of the consoles run Zilog Z-80 processors, and 4 run on some variation of the MOS 6502 made famous by the Apple 1 computer.  Later consoles shifted towards the RISC based designs of MIPS, PowerPC and the SuperH series by Hitachi (now Renesas). Today’s console continue to use RISC processors albeit at speeds of over 3GHz.

Posted in:
Just For Fun

March 27th, 2013 ~ by admin

Just for Fun: Wafers – Lots and lots of Wafers

Here at the CPU Shack I handle shipping and receiving for collectors all over the world, this means i have packages coming in daily, dozens of them.  Sometimes collectors will go in together to get a large lot of processors etc.  Today one such lot arrived, over 2200 wafers from Kokomo Semiconductor.  That’s nearly 300lbs.


Noel, the CPU Shack’s head of security, does not seem impressed.

Posted in:
Just For Fun

March 23rd, 2013 ~ by admin

Intel Pentium Processor Turns 20 Years Old

Intel Pentium 60

Intel Pentium 60 – Produced May 1993

On March 22nd, 1993 the Intel Pentium Processor was released to the public (so yah yesterday but hey whose counting). This was Intel’s first processor with an actual name.  Turns out you cannot trademark a number, so the ‘486’ name was being used by everyone (AMD, Cyrix, TI, UMC, IBM etc).  Initially known by its core name, P5, the Pentium was also the first superscaler Intel x86 processor   It had dual Integer pipelines, and a single Floating point unit allowing it to issue and complete multiple instructions per clock.

The first Pentiums ran at 60 and 66MHz and were made on a CMOS 0.8micron process with 3.2 million transistors.  After only a few months it was discovered that they ran particularly warm and the package was updated with a Copper-Tungsten heatspreader (gold plated).

A modern desktop processor such as the Core i7 Quad Core Ivy Bridge contain 1.4 Billion transistors on a 22nm process.  The P5 still lives on in the embedded market, and in the Intel Larrabee project which is itself, an updated P54C core (supporting a few more modern features such as x86-64).

Posted in:
Just For Fun