Apple Logic Board Technical Information PDF herunterladen (Seite 12)

Although the Saturn 64K and 128K boards will appear as a 16K

RAM board to much existing software, allowing this software to

take advantage of this portion of the memory board, its real

utility lies in the ability to use the additional memory on the

board. Five software packages are provided with the 64K and 128K

RAM boards, which are designed specifically to utilize all of the

memory on these boards. In fact, more than one board (as well as

a variety of other RAM boards) may be used with this software.

Any combination of the following, up to a total of 256K of

external RAM, are supported.

1. Saturn 64K RAM Boards

2. Saturn 128K RAM Boards

3. Saturn 32K RAM Boards

4. Standard 16K RAM Boards

III. SPECIAL TREATMENT FOR THE APPLE LANGUAGE CARD

The Apple Language Card must be given special consideration.

The reason for this is because it contains an Autostart ROM which

is always enabled (on) whenever the RAM on the card is disabled.

This results in a conflict when any other memory card is present

in the system in addition to the language card. A special

provision has been made in the MOVEDOS, RAMEXPAND and PASCAL

PSEUDO—DISK software packages to accomodate this conflict.

What actually occurs in these cases is that the memory space

occupied by the AUTO—START ROM ($F800 — $FFFF) is specifically

avoided by the above software so that a memory conflict will

never occur. Avoiding this space results in the inability to use

2K out of every 16K bank of every memory card in the system.

For example:

Memory Cards Present Available Memory with

(exclusive of language card) Apple Language Card present

1 Saturn 32K RAM (2 — 16K banks) 44K

1 Saturn 64K RAM (4 — 16K banks) 72K

1 Saturn 128K RAM (8 — 16K banks) 128K

Thus, when an Apple Language card is added to a system

containing a 128K board, the increase in space (16K) is exactly

matched by the space made unavailable on the 128K board (8 x 2K)

due to the presence of the language card. As a result, no

benefit is gained by having the language card in the system at

this point.

The current versions of the DOS and CP/M pseudo—Disks

(Chapters 6 and 8) DO NOT have the necessary special provisions

so as to avoid this address conflict and therefore cannot be used

in a system which contains the Apple Language Card in addition to

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