Gestetner A193 Service Manual page 800

2.3.2 Printer Enhancement Unit
D5001
A D5001 ASIC is used in this unit. It performs the following functions.
• Data compression/reconstruction
• Halftone painting
• Horizontal line filling
• Right and left edge clipping
• Line drawing with or without pattern
Z85230
The Z85230 is an enhancement serial communication controller (ESCC).
ROM
Two Mbytes of ROM are used for storing the PostScript Level 2 code and the
font data.
RAM
Two Mbytes of DRAM are provided on the board. It consists of 4 pieces of 4
Mbit fast page mode DRAM (256k x 16 DRAM) as well as the printer
controller. Together with the 2 MB DRAM on the printer controller, a minimum
4 Mbytes of memory is available when the printer enhancement unit is
installed.
2.4 Hard Disk Drive
Operation
The disk is formatted if the "HD initialize" function is used (this is a user
function). It takes about 15 minutes. "Formatting HD" is indicated during
formatting. Two partitions are made when formatting. The ratio of the first to
the second is 1:4. The first partition is for the PostScript fonts (downloaded
outline fonts and cached bitmap fonts) and the second partition is for the
sorting function.
To maintain the reliability of the disk drive and the head, if the hard disk is not
accessed for more than 10 minutes, the controller stops the disk motor and
does a seek operation (park the mag head). If inoperation continues, the
seek operation is Repeated every 10 minutes.
SM 1-11 (A643)