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The AlphaPC 264DP is a dual-processor motherboard based on the Alpha 21264 microprocessor and the 21272 core logic chipset. The CPUs and their L2 cache are on daughtercards that plug into the mainboard. Its Linux platform name is DP264, and the AlphaServer DS20 is based on the same design.

• 1 or 2 daughtercards, each with a 500 MHz Alpha 21264 CPU and 2 MiB L2 cache ¹⁾; the board supports 2 or 4 MiB, the same size on both cards ²⁾
• 21272 core logic chipset (1 Cchip, 8 Dchips, 2 Pchips)
• 16x 200-pin buffered DIMMs (four arrays of four), supports 128 MiB to 4 GiB of ECC SDRAM
• 2x 33 MHz 64-bit PCI buses
• 6x 64-bit PCI slots (one shared with ISA)
• 1x ISA slot (shared with PCI)
• Cypress CY82C693UB PCI-to-ISA bridge, IDE, keyboard, mouse, and time-of-year clock
• CR2032 coin cell (XB1) for the real-time clock ³⁾
• Adaptec AIC-7895 dual-port Ultra Wide SCSI controller
• SMC FDC37C669 Super I/O controller (floppy, 2x serial, parallel)
• Mainboard dimensions: 42.11 cm x 33.02 cm (16.58 in x 13.0 in)
• AlphaBIOS and SRM console firmware

Production boards set the configuration with switchpacks SW2 and SW3 on the mainboard and SW2 on each daughtercard; the daughtercard switches set the CPU core voltage and the flash ROM selection. ⁴⁾ The user-settable mainboard switches are: ⁵⁾

SW2-2 and SW2-3 must stay off, SW2-5 to SW2-7 must stay at the 83.3 MHz 21272 setting (off, on, on for sp2, sp1, sp0), and SW3-1 to SW3-7 must stay at their reserved settings. ⁶⁾

The three PCI slots nearest the DIMMs are on PCI bus 0, and the three nearest the board edge are on PCI bus 1, where a VGA card is not expected to work. ^{7) 8)} ATI Rage 128 and Radeon cards work in a DP264 with SRM 5.8 and later. ⁹⁾

• The original daughtercards carry 500 MHz 21264 (EV6) CPUs with 2 MiB of cache; the DS20's 500 MHz modules have 4 MiB (see CPUs). Compaq offered no official CPU upgrades for the DS20 or 264DP ¹⁰⁾, but vendors selling API products offered 667 MHz daughtercards with 4 MiB cache. ^{11) 12)}
• DS20E daughtercards are expected to work in a 264DP, but that configuration was not supported by Compaq. ¹³⁾ AlphaServer ES40 CPU daughtercards do not fit. ¹⁴⁾
• The CPU is soldered to the daughtercard, so replacing it with a faster CPU is not practical. ¹⁵⁾ A different CPU would also require matching SROM code. ¹⁶⁾

With 256 MiB DIMMs, the largest available when the board was introduced, the 16 DIMM slots hold 4 GiB. ¹⁷⁾ 512 MiB DIMMs are reported not to work in the DP264. ¹⁸⁾

The 264DP is essentially the same board as the AlphaServer DS20, ¹⁹⁾ while the DS20E has some differences. ²⁰⁾ Its SRM firmware came from Compaq, including copies distributed by API. ²¹⁾ See AlphaServer DS20 for the DS20 itself.

API's copies of the 264DP firmware are kept in the alphalinux/firmware repository: the SRM image pc264srm.rom, the AlphaBIOS image Pc264nt.sys, and an earlier package, dated August 2000, in archive/5.8. The update is run with lfu from two floppies, using pc264fw.txt as the file list. ²²⁾

• Early SRM versions did not initialize large amounts of memory correctly when os_type was set to UNIX; upgrading SRM fixes it. ^{23) 24)}
• The console prompt shows which CPU is running the console (P00>>> for CPU 0). Linux must be booted from CPU 0. ²⁵⁾

Current kernels support the AlphaPC 264DP with CONFIG_ALPHA_DP264 or a generic kernel, including both CPUs in SMP kernels; ²⁶⁾ it boots from SRM with aboot. There is no MILO for the board. ^{27) 28)} The onboard AIC-7895 SCSI controller uses the aic7xxx driver, ²⁹⁾ and the Cypress IDE controller pata_cypress. ³⁰⁾