Running "rdbinfo" on A3000 config

[mark_k]

I'm trying to set up a NetBSD 7.1 HDF to see how well WinUAE runs it. I noticed a problem on running rdbinfo. This is probably not a bug in WinUAE, but anyway...

The problem seems to be that rdbinfo issues CMD_READ to the CD drive with IO_LENGTH = 512 (when the CD sector size is 2048 bytes). That's obviously a bug in rdbinfo, but I'm just wondering would the same result happen with real hardware?

HDF and A3000/040-like config:

http://www.media!fire.com/file/bq6j5hu191jbm8k/NetBSD_4GB_HD_WIP.7z
http://www.media!fire.com/file/u6zq6ofhss9d8io/NetBSD_install_A3000_040_CDROM.uae

The config has HDF and a CD drive connected to A3000 SCSI. Boot HDF, at CLI window type rdbinfo
Something seems to hang, though you can still move the mouse pointer. Log output:
SCSI buffer 131072 -> 655360
CD SCSIEMU 0: 08.00.00.00.00.00.00.00.00.00.00.00 CMDLEN=6 DATA=09F8B020 LEN=6
CD SCSIEMU DATA: 00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00
.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00
.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00
.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00
.00.00.
-> DATAOUT=524288 ST=0 SENSELEN=0


Edit to add: some CD-ROM drives have a jumper to select the sector size, 512 or 2048 bytes...

[Toni Wilen]

It seems optical drive SCSI READ (6) blocks=0 means read nothing (but means 256 when direct access device).

Changed, not tested

[mark_k]

Is that documented anywhere? I know READ (6) support is optional for CD-ROM devices, but there's nothing in the SCSI-2 spec at least which says there's any difference in the command operation if it is implemented.

I figured it was just poor coding by the rdbinfo developer, assuming 512-byte sectors. It doesn't break when the CD drive is empty because an error is returned in response to the bogus 256-sector read. Strangely though, the reads it does do to the HD are for single sectors. (It seems to just use CMD_READ, not issue SCSI commands itself.)

[Toni Wilen]

Pioneer SCSI-2 CDROM documentatation says: "The six-byte READ command only allows reads of up to 255 blocks".

Most SCSI specs floating around are HD ("direct access") specific. Don't trust them too much.

(Yes, it is rdbinfo is also doing something wrong)

[mark_k]

I'll try to figure out what exactly rdbinfo is trying to do. What CMD_READ parameters are causing the A3000 scsi.device to issue a 256-block READ (6)?

According to a Toshiba CD-ROM SCSI spec, their drives don't support READ (6).

According to both that and the Pioneer spec, their drives allow the (logical) block size to be set by MODE SELECT; options are 512, 1024, 2048, 2336, 2340, 2352, ...

Edit: And the Hitachi GF-1050 DVD-RAM SCSI manual says it does properly support READ (6):

https://www.media!fire.com/?vwqvlkq9bvjnvm0

[Toni Wilen]

Bleh, so it depends on hardware if it works or not, so not much to do.. (and I am not going to make this optional)

READ CD command is usually used to read raw data (>2048 block sizes) and that is emulated (mainly used for audio extraction). I don't support any MODE things until program is found that needs it.