size of memini disk

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Por konamiman

Paragon (1173)

Imagen del konamiman

14-07-2009, 09:12

konamiman, can you explain why on 128K MSX2 machine the size of the disk is about 90K ?Hummm... you are right. On MSX BASIC 2.1, CALL MEMINI shows "91904 bytes allocated". But on MSX2+ and Turbo-R, you get 32000 bytes. So manuel is right: they added support for using mapped memory for the MEMINI disk in BASIC 2.1, and dropped it in BASIC 3.0. MSX2 Technical Handbook for sure refers to BASIC 2.0.

Just guessing, but by the time MSX2+ appeared, DOS 2 was already released or about to be released, so they preferred to forget about hacking the MSX BIOS and let DOS 2 do the work instead. Or, maybe the support for using mapped memory gave some incompatibility problems with old software. Go figure.

Por cax

Prophet (3738)

Imagen del cax

14-07-2009, 22:57

cax: only on MSX BASIC 2.1 machines, which are only Philips machines, AFAIK.

Add Yamaha YIS503 and YIS805 to the list.

Por mars2000you

Enlighted (6254)

Imagen del mars2000you

28-10-2015, 22:00

I know it's an old thread, but I've just found out that you can also add two Korean MSX2 machines : the Daewoo CPC-400 and CPC-400S give "91904 bytes allocated" with CALL MEMINI while CPC-300, CPC-300E, CPC-61 (and probably CPG-120) give "30000 bytes allocated".

If you check the BIOS roms, it's indicated version 2.0, but these computers don't display the version after boot. So, it's an hidden 2.1 version !!! Wink

Por mars2000you

Enlighted (6254)

Imagen del mars2000you

28-10-2015, 23:26

Little correction : it's "32000 bytes allocated" on the MSX2 machines with real BIOS 2.0.

Por madscient

Master (193)

Imagen del madscient

31-10-2015, 00:11

MEMINI on MSX-BASIC2.1 supports memory mapper.
Any other versions do NOT.

At first, MEMDISK feature was implemented for TOSHIBA HX-2x series (Japanese model) in order to effectively utilize page0-1 32KB RAM on MSX1. So memory mapper was not supported originally.
For Japanese later versions of MSX-BASIC, MEMDISK feature was inherited without almost improvement.
Because, memory mapper feature was NOT mandatory for Japanese MSX2 standard at first.

As you already saw above, MSX-BASIC2.1 with 128KB RAM, MEMINI shows about 90KB for MEMDISK.
6KB for MEMDISK management area, and 32KB for USER RAM area of BASIC.

Por mars2000you

Enlighted (6254)

Imagen del mars2000you

31-10-2015, 00:13

Check my addition to the Wiki : http://www.msx.org/wiki/CALL_MEMINI

Por madscient

Master (193)

Imagen del madscient

01-11-2015, 12:39

Additional info for HX-2x MEMDISK:
While MEMDISK feature is available, ON ERROR GOTO command does not work properly.

Por mars2000you

Enlighted (6254)

Imagen del mars2000you

01-11-2015, 12:42

Thanks for this info ! Smile

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