R800DR for DOS?

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By karloch

Prophet (2157)

karloch's picture

01-01-2011, 19:04

For years I have been using the R800 DR in order to prevent MSX to switch back to Z80 mode when accessing hard-drives. But this program can only be loaded from BASIC. It's not a big deal since I can put it at the end of my AUTOEXEC.BAT, but I'm curious about if a newer utility or a DOS version exists.

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By Manuel

Ascended (18729)

Manuel's picture

01-01-2011, 20:48

Um, why do you even need such a program? My turboR never switched back to Z80 mode when accessing harddrives... I know because on Z80 mode it is a LOT slower to even do dir.

By sd_snatcher

Prophet (3503)

sd_snatcher's picture

01-01-2011, 21:35

@Manuel

The Turbo-R disk-BIOS v2 is sneaky. It switches a lot to the Z80 (on every FDC access) without updating the Turbo Led. The mentioned tool disables this behavior and the throughput is improved.

@karloch

AFAICR, the program "DOS2CASH" also had an option to force R800 access on drives. With the advantage of installing a disk-cache too. The sad part is that it isn't compatible with the FAT16 driver.

By NYYRIKKI

Enlighted (5917)

NYYRIKKI's picture

02-01-2011, 07:16

I noticed, that R800-DR.GEN can not be compiled for DOS because of two little bugs in the source. Here is how to fix them:

- Find "defile" it looks like this:

defile:	di
	push de
	call move_system ; verschuif de systeem data
	pop de

- add before push de "if .not. dos"
- add after pop de "endif"

In "chk_computer" routine there is instruction "ld a,(#2d)" change it to:

	if dos
	ld hl,#2d
	ld a,(#fcc1)
	call #c ; rdslot
	else
	ld a,(#2d)
	endif

By Retrofan

Paragon (1264)

Retrofan's picture

02-01-2011, 09:39

For years I have been using the R800 DR in order to prevent MSX to switch back to Z80 mode when accessing hard-drives. But this program can only be loaded from BASIC. It's not a big deal since I can put it at the end of my AUTOEXEC.BAT, but I'm curious about if a newer utility or a DOS version exists. You also could use FASTDRIV.COM. Don't know where to find it, but if you need it, I have it for you. I always use it on my TurboR for R800 diskaccess.

By gdx

Enlighted (5354)

gdx's picture

01-11-2015, 10:28

Bump! Smile

A fixed version of R800-DR is available on Sharksym's website (since August month).

http://sharksym.egloos.com/5280467

Benchmark on the original Sunrise CF:

DSPEED.COM
Acces Time: 796 -> 446
Transfer Rate: 1405 -> 2507 Kbit/sec

DOSSCAN.COM
Transfer Rate: 175 -> 314 Kbit/sec

(R800-DR.COM not installed -> installed)

B-)

By Manuel

Ascended (18729)

Manuel's picture

01-11-2015, 11:08

Weird, I never used such a tool and got about 400kB/s in dosscan on my turbo R with Novaxis SCSI....

By gdx

Enlighted (5354)

gdx's picture

01-11-2015, 11:26

It depends surely on the disc. I use a old CF card of 1GB.
Your access time is how much?

By Daemos

Paragon (1959)

Daemos's picture

01-11-2015, 11:38

Some time ago I made a ROM file that can be used to boot the system into R800 DRAM mode after wich the system is unable to switch back to Z80 mode. I used this ROM to play some floppy based games with R800 enabled. I also made a .COM file that does the same thing. Solution for your problem karloch?

By gdx

Enlighted (5354)

gdx's picture

01-11-2015, 12:14

The MSX Datapack vol.3 says : It is possible to enable the Z80 / R800 ROM mode anytime but enable the R800 DRAM mode only during or just after the boot of MSX and keep this mode until next the reset or shutdown. Otherwise the MSX may be unstable.

By Manuel

Ascended (18729)

Manuel's picture

01-11-2015, 13:04

Gdx, no idea I never measured that. This was about 12 years ago on a 1GB SCSI disk.

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