Product Support Bulletin

PSB No: S-0047C
Page: 6 of 6
Q17.
A.
Q18.
A.
Q19.
A.
Q20.
A.
Are there any general guidelines for determining the chip speed to
install on the memory expansion boards?
Yes, if the CPU speed is 8MHz or less, use 150ns RAM chips. If
the CPU speed is 10/12MHz, use 120ns RAM chips.
Is there anything that should be kept in mind during the installation
procedure for the memory expansion boards?
Yes, when installing the memory boards in the Equity II + and Equity
Ill + (12MHz models), remember that the bus speed is 12MHz. For
example, the Intel Above Board 288 and Above Board Plus allow
you to set up the bus speed and chip speed in their installation
programs.
What is meant by backfilling memory when using software such as
DESQview?
Backfilling is a function of many expanded memory boards which
allows a portion of the board’s memory to be used as conventional
memory. In this way, you could turn a 256K system into one with
840K memory or more. In certain situations, you may want to
disable some of the computer’s conventional memory and the use
the memory on the expansion board (i.e. DESQview).
Which Epson computers have memory settings that allow backfilling
memory?
The Equity I, Equity I +, Equity II + and Equity Ill + allow backfill.
The Equity I comes with 256K standard and the Apex comes with
512K, thus allowing backfill. The Equity I + has DIP switch settings
allowing system memory to be disabled to 256K or 512K. The
Equity II+ and Equity Ill + have jumpers on the system memory
boards to allow memory to be disabled to 256K and 512K.