Service manual

Introduction 1-7
The KN7CG processor module has two Alpha 21264 chips, with a clock speed of
525 MHz. The KN7CH processor module has two 21264A chips, with a clock
speed of 700 MHz. If one of the CPUs on the processor module is
malfunctioning, you replace the entire module. The chip is not a field-
replaceable unit (FRU). The console display (see Section 3.1) shows each
processor on a module.
Figure 1-3 shows the processor module. The raised blocks in the figure
represent heatsinks that cover the chips.
➊
CPU chips. Each 21264(A) chip has a separate address and data bus for
B-cache and system operations. The 21264(A) chip has a 64-Kbyte
instruction cache and a 64-Kbyte data cache.
➋
Cache Memory. 4-Mbyte L2 cache per CPU (21264) and 8-Mbyte ECC
L2 onboard cache per CPU (21264A).
➌
TCC. The TurboLaser control chip (TCC) takes commands from both
CPUs and issues them to the TLSB. It also controls all data movements
through the TDI and SWI chips.
➍
SWIs. Two swizzle (SWI) chips receive data from the 256-bit wide DLSB
and pass it to one of the CPU chips over the 64-bit wide data interface
bus.
➎
TDIs. Four TurboLaser Data Interface (TDI) chips receive data from the
TLSB and pass the data over the DLSB to the two SWI chips.
➏
DC to DC Converters. These converters step the 48 VDC power
supplied by the power subsystem to the voltages required by the
components on the processor board.