DEC 4000 AXP

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The DEC 4000 AXP is a series of departmental server computers developed and manufactured by Digital Equipment Corporation introduced in 10 November, 1992. These systems formed part of the first generation of systems based on the 64-bit Alpha AXP architecture and at the time of introduction, ran Digital's OpenVMS AXP or OSF/1 AXP operating systems.

The DEC 4000 AXP was succeeded by the end of 1994 by the AlphaServer 2000 and 2100 departmental servers.

Contents 1 Models 2 Description 2.1 CPU module 2.2 Memory module 2.3 I/O module 2.4 Storage 2.5 Expansion 3 References 4 Notes

[edit] Models

There are two models of the DEC 4000 AXP:

• Model 6x0, code named Cobra: 160 MHz DECchip 21064 (EV4) processor(s) with 1 MB^[1] L2 cache each.
• Model 7x0, code named Fang: 190 MHz DECchip 21064 (EV4) processor(s) with 4 MB L2 cache each.

The possible values of 'x' is 1 or 2. These numbers specify the number of microprocessors in the system.

[edit] Description

The DEC 4000 AXP are 2-way SMP capable systems housed either in a BA640 half-height ("pedestal") cabinet, roughly the size of a photocopier, or a 19-inch rackmountable chassis (BA641). These contained a system and a storage backplane. Plugged in the backplanes were one or two CPU modules, one to four memory modules, a I/O module, six FutureBus+ Profile B expansion cards, four fixed media mass storage compartments and one removable media mass storage compartment.

[edit] CPU module

The CPU module contained a 160 or 190 MHz DECchip 21064 microprocessor, accompanied by 1 or 4 MB of Bcache (L2 cache). Two C³ (Command, Control and Communication) ASICs interfaces the module to the 128-bit address and data multiplexed system bus, which enabled communication between the CPU, memory and I/O modules.

[edit] Memory module

The memory modules are the same size as the CPU modules and contained either 64 or 128 MB of RAM organised into four banks, implemented with 280 surface mounted DIP DRAM chips that covered both sides of the board. For memory control, custom driver ASICs are used, and to interface the module to the system bus, there are two CMIC ASICs.

[edit] I/O module

The I/O module is the largest module in the system, and two variants existed. The first variant offered four SCSI-2 buses and two Ethernet ports and the second variant offered four DSSI/SCSI buses and one Ethernet port. The second variant however only has half the bandwidth of the SCSI-2 buses of the first variant, although the advanced features of DSSI justified its use in some cases. Aside from these differences, the rest of the I/O module was essentially the same.

I/O module features common to both variants are an additional SCSI-2 bus for removable media drives only, a 85C30 UART for two serial lines, a Dallas Semiconductor DS1287 real time clock, and most of the firmware in the DEC 4000 AXP. For controlling the FutureBus+ and to interface the I/O module to the system bus two IONIC ASICs are used. The Ethernet functionality in the I/O function is provided by the TGEC (Third Generation Ethernet Chip), while the SCSI/DSSI buses are provided by four NCR 53C710 SCSI/DSSI controllers and their associated DSSI drivers (second I/O module variant only).

[edit] Storage

The DEC 4000 AXP has four fixed media mass storage compartments, each capable of holding one 5¼ inch or four 3½ inch devices. A single removable media mass storage compartment provided the CD-ROM drives and tape drives. In addition to internal storage, an external storage cabinet could be attached via an external SCSI port to provide more storage.

[edit] Expansion

The DEC 4000 AXP systems used the FutureBus+ Profile B for expansion, with six slots. These slots provided a peak transfer rate of 160 MB/s.^[2]

[edit] References

• DEC 4000 AXP Model 600 Series Technical Manual, EK-KN430-TM.A01, First Printing, December 1992, Digital Equipment Corporation
• Maskas, Barry A., Shirron, Stephen F. and Warchol, Nicholas A. (1992). "Design and Performance of the DEC 4000 AXP Departmental Server Computing Systems", Digital Technical Journal 4(4).
• AlphaServer comparison chart, March 1994 edition

[edit] Notes

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