Epson EISA Desktop Product Support Bulletin page 6

Q. What is bus-mastering?
A. Bus-mastering is a method for letting a peripheral device take control of the
system. Without bus-mastering, a peripheral uses up CPU resources for
various services. A bus-mastering device is referred to as being "intelligent" -
that is, it has on-board control circuitry that lets it perform the intended function
without accessing the CPU. The EISA architecture also provides "fair
arbitration", insuring that no one device monopolizes system resources.
Q. What interfaces are provided with each system?
A. Each system includes a floppy disk drive interface (up to two drives supported),
an IDE hard disk drive interface (also supporting up to two drives), a parallel
port, two serial ports and ports for the PS/2-style keyboard and mouse.
Q. Is a video adapter included?
A. No. Due to the wide range of applications that either system may be used for,
Epson decided to let each customer pick their own display system. For
example, if the tower unit is being used as a file server, you wouldn't need the
same display capabilities as you would with the desktop unit being used as a
CAD/CAM workstation. Epson does have a VGA Option Kit available. It comes
with 1 MB of video RAM, the Sierra Hi-Color RAMDAC and supports resolutions
up to 1024 by 768 by 256 colors, interlaced and non-interlaced.
CPU/MEMORY
Q. What processor boards are available?
A. There are currently two processor boards:
486SX/25 (25 MHz); 8KB internal cache memory; sockets for optional
Weitek WTL4167 and Intel 80487SX math coprocessors
486DX/33 (33 MHz); 8KB internal cache memory; 64KB Intel 82485MA-
33 Turbocache module (write-through, two-way set associative); socket
for optional Weitek WTL4167 math coprocessor
Q. Will the 486SX/25 processor board work with the new Intel OverDrive chip?
A Yes. It installs in the 80487SX socket and provides a 50 MHz internal clock for
the CPU, as well as implementing the math coprocessor circuit.
Q. What other processor boards will be available?
A. A 486DX/50 (50 MHz) processor board will be available in the second quarter
of 1992. And, because of the modular design, future enhancements can be
quickly implemented as CPU technology advances.
PSB No: S-0139
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