The Digital Personal Workstation a-Series, code named "Miata", used the Alpha 21164A microprocessor. Models suffixed with "a" ran Windows NT (with AlphaBIOS) whereas models suffixed with "au" ran Digital UNIX or OpenVMS (with SRM). At COMDEX 1997, the Digital Personal Workstation 500a was a finalist in Byte Magazine's Best of Show award for the best workstation category.
Models included the:
- 433a/433au - 433 MHz Alpha 21164A
- 500a/500au - 500 MHz Alpha 21164A
- 600a/600au - 600 MHz Alpha 21164A
The Alpha microprocessor was socketed in a zero insertion force (ZIF) socket and could be upgraded. These workstations used Digital's 21174 chipset, also known as the "Pyxis" chipset. To increase flexibility and to reduce cost, the L3 cache was optional in these models. If the L3 cache was required, a cache module that contained the SRAMs which implemented the cache would be installed into a cache slot. The cache module had two capacities: 2 or 4 MB.
Two revisions of the Miata motherboard were produced, known as MX5 and MiataGL respectively. The later MiataGL motherboard has a revised Pyxis chipset (which fixes a PCI DMA bug), a different ATA controller, an on-board QLogic 1040 SCSI host adapter, and a USB interface.
The a-Series has a 144-bit memory bus, with 128 bits used for data and 16 bits for ECC. There are three memory banks, each consisting of two DIMM slots, for a total of six DIMM slots, which supports 32 MB to 1.5 GB of memory. The a-Series uses buffered or unbuffered PC100 ECC SD-RAM. Vendor supplied modules are twice as tall as standard DIMMs and contain two rows of SDRAMs per column instead of one. These DIMMs are installed in identical pairs in order to match the width of the memory bus. Jumer
'1' is a switch with the tab in the 'up' or 'on' position '0' is a switch with the tab in the 'down' or 'off' position If flipping the switches, use care as the switches can be delicate. Please read carefully and double check everything. Read entire document before trying anything.
Left to Right
CLK MMMM MMM RATE 6543 210N 266 -> 0000 1001 300 -> 0100 1001 333 -> 0010 1001 366 -> 0110 1001 400 -> 0001 1001 433 -> 0101 1001 - PWS 433a 466 -> 0011 1001 500 -> 0111 1001 - PWS 500a 533 -> 0000 0101 566 -> 0100 0101 600 -> 0010 0101 - PWS 600a 633 -> 0110 0101 667 -> 0001 0101 700 -> 0101 0101 733 -> 0011 0101 766 -> 0111 0101 - Kryotech? 800 -> 0000 1101
N -> Reserved - Always on Mx -> Clock multiplier digits. The lower the number, the higher the digit's significance. M0 and M6 seem to be always 0
- Template:Cite web
- Weiss, Kenneth M.; House, Kenneth A. (1997). "Digital Personal Workstations: The design of high-performance, low-cost Alpha systems". Digital Technical Journal 9 (20): pp. 45–56.