January 15th, 2017 ~ by admin

HP 1000 A700 Processor: Rise of the Phoenix

HP 12152-60002 A700 Phoenix Processor – 4x AMD AM2903 (1820-2377)

The Lighting processors of the HP A600 and A600+ were good performing for 1982.  They filled the entry and mid range slots of the HP 1000 A Series quite well.  The additional floating point support of the A600+ in 1984 helped considerably as well, but what was needed for truly better performance on the high end was hardware math support.  While the HP A600 took only 9 months to design and release, the A700, released at the same time, took somewhat longer.  The A600 was based on the AMD 2901, which had been released way back in 1975.  The A700 Phoenix was based on its successor, the AM2903.  The 2903 added a few important features to the bit-slicer.  Hardware multiply and divide support,support for more registers, and easier ways to access them, and parity generation.  This is why the A700 took longer to design, the A600 design was begun half way through the A700 to fill the lower end, where the features of the 2903 wouldn’t be as missed.

The A700 performs at the same 1 MIPS as the A600 but supports 205 standard instructions (compared to 182 for the A600 and 239 for the A600+).  It adds more register reference instructions, dynamic  mapping, I/O and more math based instructions.  Cycle time is actually slightly slower, 250ns compared to 227ns for the A600 but the 2903 allows more efficiency making up for the difference.  A typical FMP instruction take 13.75-25.25 microseconds compared to 16.6-26.6 on the 2901 powered A600.  This is a direct result of the hardware multiply hardware included in the 2903.  The A600+, with its faster 2901C’s completes the same instruction in 17-21.1 microseconds, FASTER then the A700. But the A700 has a trick up its sleeve….

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November 26th, 2016 ~ by admin

HP 3000 Series 33: 16-bits of Sapphire

HP 3000 Series 33 - 16-bits 11MHz. They were integrated into the desk, with a 20MB hard drive on the left, and the computer on the right (with a 1.2MB 8" Floppy Drive)

HP 3000 Series 33 – 16-bits 11MHz. They were integrated into the desk, with a 20MB hard drive on the left, and the computer on the right (with a 1.2MB 8″ Floppy Drive)

In 1972 HP introduced the HP 3000 line of minicomputers.  Mini of course meaning they didn’t take up the entire room.  They competed against the likes of the DEC PDP-11 and the TI-990.  Original called the System/3000 (apparently to compare favorably to the IBM System/360) they were renamed the HP 3000.  These were 16-bit computers employing a stack based design,  They had no general purpose registers, all operations operated directly on one of several stacks.  The first models were designed using bipolar discrete logic and ROM for the microcoding.  This allowed for good performance but was expensive and large.  Just the processor for the high end Series III of 1978 was 9 boards.

The Series 33 (and the smaller series 30) were to be cost reduced versions, to slot in between the high end Series III and the newly introduced HP 300 microcomputer.  In order to do this those 9 boards for the processor needed to be greatly simplified.  HP engineers decided to use a processor they had already, the CPU from the HP 300 Amigo.  The HP Amigo was a bit of a disaster for HP, after 5 years of development, including

1AB4-6003 RALU -Silicon on Sapphire - 8000 Transistors

1AB4-6003 RALU -Silicon on Sapphire – 8000 Transistors

designing an entirely new processor it was a failure in the market, suffering from management and politics more then from a technical standpoint (it was not file system compatible with the 3000 line and that caused some concerns).  After being released in 1978 it made only around $15 million in sales and was canceled after a short time.

Part of that 5 year development was for its 16-bit VLSI processor.  In order to get the speed needed for the HP 300 and at a low price, the pressor needed to be a VLSI design (a few chips rather then a few boards).  In order to fit in a smaller pedestal cabinet it needed to energy efficient and heat efficient as well.  HP’s engineers decided to use a Silicon On Sapphire (SoS) CMOS design, a process HP had some great experience with in the MC2 processor.  SoS is a form of Silicon on Insulator, a manufacturing method that is very common in today’s IC’s (using Silicon Dioxide).  Instead of an IC being made on a pure silicon wafer, the silicon is deposited on a wafer of sapphire.  Sapphire is an excellent insulator which wels reduce leakage currents, as well as spurious currents from such things as radiation.  Radiation tolerance is perhaps what SoS became known for most, but its low power performance was what HP was after in the 1970’s.

Die shot of the RALU with labels.

Die shot of the RALU with labels.

The processor for the HP 300 was designed into 3 separate IC’s, totaling 20,000 transistors (some documentation says 25,000) and running at a clock of 11MHz.  The processor control unit (PCU 1AB2-6003) chip generates microinstruction addresses that control the other two chips: the register, address, skip, and special (RASS 1AB3-6003) chip and the register, arithmetic, and logic unit (RALU 1AB4-6003) chip.

The PCU contains 5000 transistors and handles the microsequencing, clock generation, and a sub-routine save stack.  Clock generation is interesting as its single phase, and variable.  The PCU can lengthen or shorten the clock period as needed.  If a memory operation needs longer to complete the PCU simply holds the lock period longer.  Data path functions are handled by the RASS and RALU chips.  The RASS contains about 7000 transistors and contains a register file for the second operand to the RALU as well as address generation and skip logic.  The largest of the chips is the RALU.  It handles all of the standard ALU functions as well as hardware multiply/divide.  It also contains 16 registers: 8 general purpose registers, and 8 for address storage.  Together these three chips form the CPU of the HP 300 and consume only 1Watt of power.  The processor is a microcoded design so the actually instruction set resides in ROM, in this case on a separate board.  In the case of the HP 300 this also allowed the I/O processor duties to be microcoded into the general processor, eliminating another subsystem.

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April 7th, 2014 ~ by admin

HP C5061-3012 16-bit Processor

HP C5061-3012 - 16 Bit - 4  MHz - 1984

HP C5061-3012 – 16 Bit – 4 MHz – 1984

In last months article on HP’s 16 bit processors we mentioned it was made in a reduced version (on an enhanced NMOS III process).  This CPU was known as the C5061-3012.  It contains only a BPC (Binary Processor Chip) and no EMC or IOC.  It was meant for simpler designs, such as a tape controller, but also in some other HP test equipment.  While a simpler implementation, it would seem that HP chose to continue the use of rather beautiful, and highly delicate packaging.  This example was made in 1984, a time when most other ICs were grey ceramic or plastic, not a white/gold ceramic package.

This was meant to mounted to a heatsink, which dissipated the heat as well as protected the wafer this ceramic (the package, other than where the die is, is less than 1mm thick)

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March 18th, 2014 ~ by admin

The Forgotten Ones: HP D5061-30xx Processors

HP D5061-3001 - 10MHz 24,000 Transistors

HP D5061-3001 – 10MHz 24,000 Transistors

40+ Years after computer processors began to be made, there are several that stick in peoples minds as ‘the greats’ as being somehow more important then others.  Processors such as the Intel 4004, the MOS 6502 of Apple fame, and the Motorola 6800 have taken histories podium as the most important.

The truth, however, is a bit different, yet no less exciting.  There are those processors that at their time, were vastly ahead of their time, such technological marvels that they continued to be competitive for a decade, impressive today, nearly unheard of in the 1970’s.  Some of these processors never saw wide use in PCs, such as the 1802 or SMS300 yet were remarkable.  Still others were designed not to be mass market, or to be licensed but to satisfy a company’s internal needs for a processor to power their equipment.   These in house designs were every bit as impressive as the competition but since they were used by their creators alone, they faded into obscurity.  One such example was the Bell Labs BELLMAC-8, designed by, and for Western Electric. They were not alone however…

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September 15th, 2013 ~ by admin

Compaq 21364 Processor – The Omega of the Alpha

Compaq 21364 Alpha Prototype - 2002

Compaq 21364 Alpha Prototype – 2002

The DEC Alpha was one of the fastest processors of the 1990’s. The original 21064, manufactured in CMOS, rivaled the fastest ECL processors and blew away most everything else.  Clock speeds were 150-200MHz (eventually hitting 275MHz) at a time when a standard Intel PC was hitting 66MHz, at the very top end. It was manufactured on a 0.75u process using 1.68 million transistors.  The Alpha was a 64-bit RISC design, at a time when 16-bit computing was still rather common.  This gave the architecture a good chance at success and a long life.

The 21064 was followed by the 21164 in 1995 with speeds up to 333MHz on a 0.5u process, now using 9.3million transistors.  It added an on die secondary cache (called the Scache) of 96KB as well as 8KB instruction and Data caches.  These accounted for 7.2 million transistors; the processor core itself was only around 2.1 million, a small increase over the 21064.  At the time the main competition was the Pentium Pro, the HP PA8800 and the MIPS R10000.  Improved versions were made by both DEC and Samsung, increasing clock speeds to 666MHz by 1998.

In 1996 DEC released the next in the series, the 21264.  The 21264 dropped the secondary cache from the die, and implemented it off chip (now called a Bcache).  The level 1 caches were increased to 64KB each for instruction and data resulting in a transistor count rise to 15.2 million, 9.2 million of which were for the cache, and the branch prediction tables.  Frequency eventually reached 1.33GHz on models fab’d by IBM. However the end of the Alpha had already begun. DEC was purchased by Compaq in 1998, in the midst of the development of the enhanced 21264A.  Compaq was an Intel customer, and Intel was developing something special to compete with the Alpha.

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January 5th, 2013 ~ by admin

2012: Year in Review: Processors and FPUs

Welcome to 2013!  2012, was a busy year here at the CPU Shack Museum. We added 716 new processors/EPROMs/MCUs, which works out to an average of 2 new chips per day.  This includes 16 New in Box Processors. We also added 53 new Graphics Processors, which isn’t bad for something we only collect on the side.

Some processor highlights (in no particular order, click to enlarge):


Here is a HP/Compaq 21364 1300MHz, this was the end of the road for the DEC Alpha architecture.  It was killed off in favor of the Itanium, for better or for worse.


The IBM POWER5+ MCM is a stunning chip to look at, clocked at 1.9GHz its a dual core with on package L3 cache


An Intel MG80387-16 SM156 US Military MIL-STD-883B spec math co processor for the 80386 processor.  Made in 1990


Going back in time further is this East German (MME) 80A CPU, a clone of  the Zilog Z80 made in 1991 (copied before unification, produced after, for this example).  Its always neat to see the white ceramic package, even well into the 1990’s.


NexGen was a company that became victim of the wild processor wars of the 1990’s.  It was bought out by AMD which used its designs as the basis of the very popular and successful AMD K6.  Here is a very uncommon 133 (rated) without FPU.  Later they made a version with an integrated FPU.


And to get all the way to ‘Z’ we shall go to the Zoran ZR36762.  Its a DVD controller SoC, with Dolby Digital support.  Not something one sees and thinks of as a processor.  However at its core, even in 2004, it is not an ARM, its not a MIPs, its a high speed (67MHz) Turbo186, the same 186 architecture Intel released in 1982, still being used, albeit in CMOS.

In the next few days I’ll post some EPROM highlights, then some GPU highlights.  2013 is already off to a great start with new chips coming in each week.