Alpha 21164
Encyclopedia
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
developed and fabricated by Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
that implemented the Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
instruction set architecture (ISA). It was introduced in January 1995, succeeding the Alpha 21064A
Alpha 21064
The Alpha 21064 is a microprocessor developed and fabricated by Digital Equipment Corporation that implemented the Alpha instruction set architecture . It was introduced as the DECchip 21064 before it was renamed in 1994. The 21064 is also known by its code name, EV4...
as Digital's flagship microprocessor. It was succeeded by the Alpha 21264
Alpha 21264
The Alpha 21264 was a Digital Equipment Corporation RISC microprocessor introduced in October, 1996. The 21264 implemented the Alpha instruction set architecture .- Description :...
in 1998.
History
First silicon of the Alpha 21164 was produced in February 1994, and the OpenVMSOpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
, Digital UNIX
Tru64 UNIX
Tru64 UNIX is a 64-bit UNIX operating system for the Alpha instruction set architecture , currently owned by Hewlett-Packard . Previously, Tru64 UNIX was a product of Compaq, and before that, Digital Equipment Corporation , where it was known as Digital UNIX .As its original name suggests, Tru64...
and Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
s were successfully booted on it. It was sampled in late 1994 and was introduced in January 1995 at 266 MHz. A 300 MHz version was introduced in March 1995. The final Alpha 21164, a 333 MHz version, was announced on 2 October 1995, available in sample quantities. The Alpha 21164 was replaced by the Alpha 21164A as Digital's flagship microprocessor in 1996 when a 400 MHz version became available in volume quantities.
Users
Digital used the Alpha 21164 operating at various clock frequencies in their AlphaServerAlphaServer
AlphaServer was the name given to a series of server computers, produced from 1994 onwards by Digital Equipment Corporation, and latterly by Compaq and HP. As the name suggests, the AlphaServers were based on the DEC Alpha 64-bit microprocessor...
servers
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
, AlphaStation
AlphaStation
AlphaStation was the name given to a series of computer workstations, produced from 1994 onwards by Digital Equipment Corporation, and latterly by Compaq and HP. As the name suggests, the AlphaStations were based on the DEC Alpha 64-bit microprocessor...
workstation
Workstation
A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems...
s. Digital also used the Alpha 21164 in their Alpha VME 5/352 and Alpha VME 5/480 single board computers and AlphaPC 164 and AlphaPC 164LX motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
s. Alpha partner Cray Research used a 300 MHz Alpha 21164 in their T3E-600
Cray T3E
The Cray T3E was Cray Research's second-generation massively parallel supercomputer architecture, launched in late November 1995. The first T3E was installed at the Pittsburgh Supercomputing Center in 1996. Like the previous Cray T3D, it was a fully distributed memory machine using a 3D torus...
supercomputer. Third parties such as DeskStation also built workstations using the Alpha 21164.
Performance
The 21164 continued the performance lead from the 275 MHz Alpha 21064A until the introduction of the IntelIntel Corporation
Intel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...
Pentium Pro
Pentium Pro
The Pentium Pro is a sixth-generation x86 microprocessor developed and manufactured by Intel introduced in November 1, 1995 . It introduced the P6 microarchitecture and was originally intended to replace the original Pentium in a full range of applications...
in November 1995, when a 200 MHz version outperformed the 300 MHz 21164 on the SPECint95 base
SPECint
SPECint is a computer benchmark specification for CPU's integer processing power. It is maintained by the Standard Performance Evaluation Corporation . SPECint is the integer performance testing component of the SPEC test suite. The first SPEC test suite, CPU92, was announced in 1992. It was...
benchmark suite. The 21164 retained its floating-point performance lead. The 333 MHz 21164 introduce the following year outperformed the Pentium Pro, but it was later surpassed by the MIPS Technologies
MIPS Technologies
MIPS Technologies, Inc. , formerly MIPS Computer Systems, Inc., is most widely known for developing the MIPS architecture and a series of pioneering RISC chips. MIPS provides processor architectures and cores for digital home, networking and mobile applications.MIPS Computer Systems Inc. was...
R10000
R10000
The R10000, code-named "T5", is a RISC microprocessor implementation of the MIPS IV instruction set architecture developed by MIPS Technologies, Inc. , then a division of Silicon Graphics, Inc. . The chief designers were Chris Rowen and Kenneth C. Yeager...
and then by the Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
PA-8000
PA-8000
The PA-8000 , code-named Onyx, is a microprocessor developed and fabricated by Hewlett-Packard that implemented the PA-RISC 2.0 instruction set architecture . It was a completely new design with no circuitry derived from previous PA-RISC microprocessors...
in the same year.
Description
The Alpha 21164 is a four-issue superscalarSuperscalar
A superscalar CPU architecture implements a form of parallelism called instruction level parallelism within a single processor. It therefore allows faster CPU throughput than would otherwise be possible at a given clock rate...
microprocessor capable of issuing a maximum of four instructions per clock cycle
Clock signal
In electronics and especially synchronous digital circuits, a clock signal is a particular type of signal that oscillates between a high and a low state and is utilized like a metronome to coordinate actions of circuits...
to four execution units: two integer
Integer
The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...
and two floating-point. The integer pipeline is seven stages long, and the floating-point pipeline is ten stages long. The 21164 implemented a 43-bit virtual address
Virtual address
In computer technology, a virtual address is an address identifying a virtual, i.e. non-physical, entity.-Description:The term virtual address is most commonly used for an address pointing to virtual memory or, in networking, when referring to a virtual network address...
and a 40-bit physical address
Physical address
In computing, a physical address, also real address, or binary address, is the memory address that is represented in the form of a binary number on the address bus circuitry in order to enable the data bus to access a particular storage cell of main memory.In a computer with virtual memory, the...
. It was therefore capable of addressing 8 TB of virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
and 1 TB of physical memory.
Integer unit
The integer unit consisted of two integer pipelines and the integer register fileRegister file
A register file is an array of processor registers in a central processing unit . Modern integrated circuit-based register files are usually implemented by way of fast static RAMs with multiple ports...
. The two pipelines, the add pipeline and the multiply pipeline are not identical, each are responsible for executing different instructions, although both are capable of executing common add, logical, load, compare, and conditional move instructions. The multiply pipeline exclusively executes shift, store, and multiply instructions (in a non-pipelined multiplier). The add pipeline exclusively executes branch instructions.
Except for branch, conditional move, and multiply instructions, all other instructions begin and finish execution during stage five for a one cycle latency. Branch and conditional move instructions are executed during stage six so they can be issued with a compare instruction whose result they depend on.
The integer register file contained forty 64-bit registers, of which thirty-two are specified by the Alpha Architecture and eight are for use by PALcode
PALcode
In computing, in the Alpha instruction set architecture, PALcode is the name used by DEC for a set of functions in the SRM or AlphaBIOS firmware, providing a hardware abstraction layer for system software, covering features such as cache management, translation lookaside buffer miss handling,...
as scratchpad memory. The register file has four read ports and two write ports evenly divided between the two integer pipelines.
Floating-point unit
The floating-point unit consisted of two floating-point pipelines and the floating point register file. The two pipelines are not identical, one executed all floating-point instructions except for multiply, and the other executed only multiply instructions. Both pipelines have four stages. A non-pipelined floating-point divider is connected to the add pipeline. All floating-point instructions except for divide have four-cycle latency. Divides have variable latency that depends on whether the operation is being performed on single or on double precisionDouble precision
In computing, double precision is a computer number format that occupies two adjacent storage locations in computer memory. A double-precision number, sometimes simply called a double, may be defined to be an integer, fixed point, or floating point .Modern computers with 32-bit storage locations...
floating-point numbers and numbers themselves. Including overhead, single precision divides have a 15- to 31-cycle latency, whereas double precision divides have a 22- to 60-cycle latency.
Cache
The 21164 has three levels of cacheCPU cache
A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations...
, two on-die and one external and optional. The caches and the associated logic consisted of 7.2 million transistors.
The primary cache is split into separate caches for instructions and data, referred to as the I-cache and D-cache respectively. They are 8 KB in size, direct-mapped and have a cache line size of 32 bytes. The D-cache is dual-ported, to improve performance, and is implemented by duplicating the cache twice. It uses a write-through write policy and an on-read allocation policy.
The secondary cache, known as the S-cache, is on-die and has a capacity of 96 KB. An on-die secondary cache was required as the 21164 required more bandwidth than an external secondary cache could supply in order to provide it with enough instructions and data. The cache required two cycles to access due to its large area. To improve performance, the cache is pipelined. Another benefit of an on-die secondary cache was that it could be easily implemented as a multi-way cache, and as a result, the cache is three-way set associative, offering improved hit rates than direct-mapped caches. The S-cache, due to the large physical area required, was implemented in two halves which flank the I-box, E-box, F-box and M-box. This was done so the cache could return data in two cycles.
The tertiary cache, known as the B-cache, is implemented with external SRAMs. The B-cache was optional and some systems using the Alpha 21164 did not have any. The B-cache could have a capacity of 1 to 64 MB, smaller capacities were not supported as they were rendered useless by the on-die S-cache. It is direct-mapped, uses a write-back write policy and a on-write allocation policy. The B-cache is controlled by on-die external interface logic, unlike the 21064, which required an external cache controller. The B-cache could be built with asynchronous or synchronous SRAMs. The B-cache is accessed via the system bus.
External interface
The external interface is a 128-bit system bus. The system bus operates at a clock frequency that is 3 to 15 times lower than the internal clock frequency, or 20 to 100 MHz with an internal clock frequency 300 MHz. The system bus' clock signal is generated by the microprocessor.Clock
The internal clock frequency is generated by dividing an external clock signal by two. The Alpha 21164 therefore requires an external clock signal which supplies a clock signal whose clock frequency is twice the desired internal clock frequency, eg. 600 MHz for a 300 MHz Alpha 21164.Fabrication
The Alpha 21164 contains 9.3 million transistors on a dieDie (integrated circuit)
A die in the context of integrated circuits is a small block of semiconducting material, on which a given functional circuit is fabricated.Typically, integrated circuits are produced in large batches on a single wafer of electronic-grade silicon or other semiconductor through processes such as...
measuring 16.5 by 18.1 mm (299 mm2), which was close to the maximum limits of the process. The die was fabricated in Digital's fifth-generation complementary metal–oxide–semiconductor
CMOS
Complementary metal–oxide–semiconductor is a technology for constructing integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits...
(CMOS) process, CMOS-5, a 0.50 µm process with four levels of aluminium interconnect. The 21164 used a 3.3-volt
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
(V) power supply. It dissipated 46 W at 266 MHz, 51 W at 300 MHz, 56 W at 333 MHz.
Package
The Alpha 21164 is packaged in a 499-pin ceramic interstitial pin grid arrayPin grid array
A pin grid array, often abbreviated PGA, is a type of integrated circuit packaging. In a PGA, the package is square or roughly square, and the pins are arranged in a regular array on the underside of the package...
(IPGA) measuring 57.40 by 57.40 mm. The package had a heat spreader
Heat spreader
A heat spreader is most often simply a copper plate, having high thermal conductivity. Functionally, it is a heat exchanger that moves heat between a heat source and a secondary heat exchanger whose surface area and geometry are more favorable. By definition, the heat is "spread out", such that...
with two studs to which the heat sink
Heat sink
A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat sinks are the heat exchangers used in refrigeration and air conditioning systems and the radiator in a car...
was bolted to.
Alpha 21164 (EV56)
History
It was first described in October 1995 at the Microprocessor Forum. On 13 November 1995, Digital announced that samples would ship later in the month. The first version, operating at 366 MHz, was introduced in 1996. On 8 July 1996, Digital announced that a 433 MHz version was available and a 500 MHz version was sampling with volume quantities due in September 1996. The 433 MHz version was priced at $1,492 per unit in quantities of 1,000. The 600 MHz version was introduced on 31 March 1997, shipping in volume quantities. Samsung ElectronicsSamsung Electronics
Samsung Electronics is a South Korean multinational electronics and information technology company headquartered in Samsung Town, Seoul...
signed a deal with Digital in June 1996 to second source
Second source
In the electronics industry, a second source is a company that is licensed to manufacture and sell components originally designed by another company ....
the Alpha 21164A and the company was the only one to fabricate the 666 MHz model. 366 to 500 MHz samples were introduced on 11 November 1996 with volume availability in 1997. The Alpha 21164A was fabricated at Digital's Hudson, Massachusetts
Hudson, Massachusetts
Hudson is a town in Middlesex County, Massachusetts, United States. The population was 19,063 at the 2010 census. The town is located in central Massachusetts, about a 40-minute drive, or about , west of Boston, and about a 20-minute drive, or about , northeast of Worcester.Before its...
and Samsung's Kihueng, South Korea fabrication plants.
Users of the Alpha 21164A included Cray Research, Digital, Network Appliance (now NetApp), and DeskStation. Cray Research used 450, 600 and 675 MHz Alpha 21164As in later models of their T3E
Cray T3E
The Cray T3E was Cray Research's second-generation massively parallel supercomputer architecture, launched in late November 1995. The first T3E was installed at the Pittsburgh Supercomputing Center in 1996. Like the previous Cray T3D, it was a fully distributed memory machine using a 3D torus...
supercomputer. Digital used the Alpha 21164A operating at various clock frequencies in their AlphaServer
AlphaServer
AlphaServer was the name given to a series of server computers, produced from 1994 onwards by Digital Equipment Corporation, and latterly by Compaq and HP. As the name suggests, the AlphaServers were based on the DEC Alpha 64-bit microprocessor...
s, AlphaStation
AlphaStation
AlphaStation was the name given to a series of computer workstations, produced from 1994 onwards by Digital Equipment Corporation, and latterly by Compaq and HP. As the name suggests, the AlphaStations were based on the DEC Alpha 64-bit microprocessor...
s, Celebris XL workstations and Digital Personal Workstation
Digital Personal Workstation
The Digital Personal Workstation is a family of entry-level to mid-range workstation computers developed and manufactured by Digital Equipment Corporation . These workstations are based on the DEC Alpha and Intel Pentium Pro or Pentium II microprocessors...
s. NetApp used 400, 500 and 600 MHz Alpha 21164As in their storage systems
NetApp filer
In computer storage, NetApp filer, known also as NetApp Fabric-Attached Storage , or NetApp's network attached storage device are NetApp's offering in the area of Storage Systems. A FAS functions in an enterprise-class Storage area network as well as a networked storage appliance...
. DeskStation used the Alpha 21164A in their Raptor Reflex workstations.
Description
The most notable change was the inclusion of Byte Word Extensions (BWX), an extension to the Alpha Architecture designed to improve byte and word accesses. These instructions are executed by the multiply pipeline. The Alpha 21164A contained 9.66 million transistors on a die measuring 14.4 mm by 14.5 mm, for a die area of 209 mm2. Digital fabricated the die in their sixth generation CMOS process, CMOS-6, a 0.35 µm process with four layers of interconnect. Samsung fabricated the die in their 0.35 µm process with four layers of interconnect based on a 0.3 µm process they developed in early 1996. The Alpha 21164A used a 3.3 V power supply, dissipating 31.0 W at 366 MHz, 36.0 W at 433 MHz, 41.0 W at 500 MHz, 43.5 W at 533 MHz and 48.5 W at 600 MHz.Alpha 21164PC (PCA56)
The Alpha 21164PC, also known as the PCA56, is a low-cost version of the Alpha 21164A introduced on 17 March 1997. The microprocessor was jointly developed by Digital and Mitsubishi Electric CorporationMitsubishi Electric
is a multinational electronics and information technology company headquartered in Tokyo, Japan. It is one of the core companies of the Mitsubishi Group....
, and both companies fabricated the design. Mitsubishi later suspended the joint development agreement for future Alpha microprocessors with Digital in early 1998 and ceased to fabricate the Alpha 21164PC in mid-1998, exited the Alpha market because the economic conditions in the company's markets.
The Alpha 21164PC operated at clock frequencies of 400, 466 and 533 MHz. Major changes are the omission of the S-cache, a larger I-cache, and the inclusion of Motion Video Instructions (MVI), an extension to the Alpha Architecture which introduced single instruction multiple data
SIMD
Single instruction, multiple data , is a class of parallel computers in Flynn's taxonomy. It describes computers with multiple processing elements that perform the same operation on multiple data simultaneously...
(SIMD) instructions for improving the performance of MPEG encoding. The S-cache was removed to reduce the transistor count, which reduced the die size and in turn, cost. The I-cache was doubled in capacity to 16 KB from 8 KB to compensate for the lack of S-cache, as the Alpha 21164 relied on the S-cache to complement the I-cache in order to provide enough bandwidth to achieve adequate performance. The amount of B-cache was limited to 512 KB to 4 MB, with 1 and 2 MB capacities also supported. The microprocessor uses a 43-bit virtual address and 33-bit physical address.
The Alpha 21164PC contained 3.5 million transistors on a die measuring 8.65 by 16.28 mm, for a die area of 141 mm2. Digital fabricated the die in the same process as the Alpha 21164, CMOS-5. The Alpha 21164PC was packaged in 413-pin IPGA measuring 49.78 by 49.78 mm. It used a 3.3 V power supply, dissipating 26.5 W at 400 MHz, 30.5 W at 466 MHz and 35.0 W at 533 MHz.
The Alpha 21164PC was used by Digital in their AlphaPC 164SX motherboard.
Alpha 21164PC (PCA57)
A derivative of the PCA56, the PCA57 was designed and fabricated by Samsung ElectronicsSamsung Electronics
Samsung Electronics is a South Korean multinational electronics and information technology company headquartered in Samsung Town, Seoul...
in a 0.28 µm CMOS process. The PCA57 was introduced in late 1998 and operated at clock frequencies of 533, 600 and 666 MHz. Improvements to the PCA56 microarchitecture included doubled I-cache and D-cache capacities: 32 KB and 16 KB respectively. The PCA57 contained 5.7 million transistors on a die measuring 6.7 mm by 15 mm, for a die area of 101 mm2. It operated on a 2.5 V power supply and dissipated 18 W at 533 MHz, 20 W at 600 MHz and 23 W at 666 MHz.
The PCA57 was used by Digital in its AlphaPC 164RX motherboard.
Chipsets
Digital and VLSI Technology developed chipsets for the 21164 and its derivatives. Digital also developed custom application-specific integrated circuitApplication-specific integrated circuit
An application-specific integrated circuit is an integrated circuit customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC...
(ASICs) for use in the high-end models of their AlphaServer
AlphaServer
AlphaServer was the name given to a series of server computers, produced from 1994 onwards by Digital Equipment Corporation, and latterly by Compaq and HP. As the name suggests, the AlphaServers were based on the DEC Alpha 64-bit microprocessor...
family such as the AlphaServer 8200 and 8400.
21171
The 21171, also known as Alcor, was the first chipset for the 21164, introduced in January 1995 alongside the microprocessor it supports. It was developed and fabricated by Digital. The 21171 is an upgraded DECchip 21071 modified to support the new system bus protocol the 21164 uses. It consisted of a control chip that contained the memoryMemory controller
The memory controller is a digital circuit which manages the flow of data going to and from the main memory. It can be a separate chip or integrated into another chip, such as on the die of a microprocessor...
and PCI controllers, and four data slice chips that interfaced the 256-bit memory bus
Memory bus
The memory bus is the computer bus which connects the main memory to the memory controller in computer systems. Originally, general-purpose buses like VMEbus and the S-100 bus were used, but to reduce latency, modern memory buses are designed to connect directly to DRAM chips, and thus are...
and PCI bus to the system bus. The 21171 provides a 64-bit wide PCI bus that runs at 33 MHz.
Pyxis
The Pyxis chipset, also known as the 21174, supported the 21164A and 21164PC microprocessors. Unlike previous chipsets, it was designed for low-cost systems. As a result, it was a single-chip design packaged in a 474-contact ceramic ball grid array (CBGA) instead of multiple packages. It was subsequently used in cost-sensitive applications such as entry-level workstations (Digital Personal Workstation a-SeriesDigital Personal Workstation
The Digital Personal Workstation is a family of entry-level to mid-range workstation computers developed and manufactured by Digital Equipment Corporation . These workstations are based on the DEC Alpha and Intel Pentium Pro or Pentium II microprocessors...
) and motherboards such as the AlphaPC 164LX and 164SX. When it was introduced, the 21174 was priced at US$142 in quantities of 1,000.
The 21174 contains a memory controller and PCI controller. The memory controller supported up to 512 MB of synchronous dynamic random access memory
Synchronous dynamic random access memory
Synchronous dynamic random access memory is dynamic random access memory that is synchronized with the system bus. Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs...
(SDRAM) and accesses it via a 128-bit memory bus
Memory bus
The memory bus is the computer bus which connects the main memory to the memory controller in computer systems. Originally, general-purpose buses like VMEbus and the S-100 bus were used, but to reduce latency, modern memory buses are designed to connect directly to DRAM chips, and thus are...
. The memory can be either ECC or parity protected. The PCI controller provided a PCI or PCI-X
PCI-X
PCI-X, short for PCI-eXtended, is a computer bus and expansion card standard that enhances the 32-bit PCI Local Bus for higher bandwidth demanded by servers. It is a double-wide version of PCI, running at up to four times the clock speed, but is otherwise similar in electrical implementation and...
bus.
Polaris
Polaris is a system controller developed by VLSI TechnologyVLSI Technology
VLSI Technology, Inc was a company which designed and manufactured custom and semi-custom ICs. The company was based in Silicon Valley, with headquarters at 1109 McKay Drive in San Jose, California...
for personal computers that supports the 21164A and 21164PC microprocessors. Polaris was announced on 16 June 1997. It supports up to 768 MB of EDO DRAM or up to 512 MB of SDRAM. The memory is accessed via a 128-bit bus. It provides a 32-bit, 33 MHz PCI bus for I/O.
Users of Polaris included Digital, for its AlphaPC 164RX motherboard.
Further reading
- Bannon, P., Saito, Y. (1997). "The Alpha 21164PC microprocessor". Proceedings of Compcon '97, pp. 20–27.
- Bhandarkar, Dileep P. (1995). Alpha Architecture and Implementations. Digital Press.
- Carlson, D. et al. (1998). "A 667 MHz RISC microprocessor containing a 6.0 ns 64 b integer multiplier". ISSCC Digest of Technical Papers, pp. 294–295.
- Carlson, D.A.; Castelino, R.W.; Mueller, R.O. (November 1997). "Multimedia extensions for a 550-MHz RISC microprocessor". IEEE Journal of Solid-State Circuits 32 (11): pp. 1618–1624.
- Jain, A.K. et al. (1997). "1.38 cm2 550 MHz microprocessor with multimedia extensions". ISSCC Digest of Technical Papers, pp. 174–175, 451.
- Gronowski, Paul E. et al. (May 1998). "High-performance microprocessor design". IEEE Journal of Solid-State Circuits 33 (5): pp. 676–686.
- Kobayashi, S. et al. (1997). "A 550 MHz Alpha microprocessor targeted at PC applications". Proceedings of the 1997 International Symposium on VLSI Technology, Systems, and Applications, pp. 203–207.