Hi ppl, here is a lightweight question for those who are in summer
holidays and have therefore a lot of time for MSX investigation.
It is about how the memory is used in the BASIC environment when disk
interface is present. MSX2 Technical Handbook says that it is as
follows:
- Up to HIMEM (&HFC4A), normal BASIC memory.
- From BLDCHK+1 (&HF377+1), BLOAD/BSAVE routines, 25 bytes. This
variable points to the same address as HIMEM.
- From FCBBASE (&HF353), space for disk FCBs of disk files opened by
BASIC (this area is 37*7 bytes, so a maximum of MAXFILES=6 can be used,
FCB 0 is used for BLOAD/BSAVE). Note that this is not the same as the
FCBs area in the normal BASIC memory (267 bytes * (MAXFILES+1))
- From HIMSAV (&HF349), the general disk work area starts. This area
exists also in DOS mode.
I have seen that this scheme is followed exactly in this way in DOS 1.
However in DOS 2 it is different:
- Up to HIMEM (&HFC4A), normal BASIC memory.
- From HIMEM to HIMSAV there is an apparently unused area of 525 bytes.
- From HIMSAV, the general disk work area starts. BLDCHK+1 and FCBSAVE
point to somewhere into this area.
And the question is: what is this 525 bytes "ghost" area for? May it be
reused for BASIC programs (doing a CLEAR up to the address pointed by
HIMSAV) safely? 525 bytes is really much memory when using the BASIC
environment.
OK, so go for it, the first person replying this question will earn 100
points!
*** XXIV MSX USERS MEETING IN BARCELONA: DECEMBER ??th 2003 ***
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Konami Man - AKA Nestor Soriano (^^)v
http://www.konamiman.com - [EMAIL PROTECTED]
ICQ#: 18281450
Itoshii hito no tame ni Ima nani ga dekiru ka na?
Kanawanai yume wa nai yo! Massugu ni shinjiteru
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