Issue with SD card on SC131

[Marc Kip]

Hello all,

I'm a newbie on the SC131 but managed to get it to boot. It will perfectly load the build-in CP/M with option "C". Everything seems to run fine. Rom version is RomWBW HBIOS v3.5.1, 2025-05-21

The issue starts with the SD card. I have read the User Guide, especially the sections 3,4 and 5. I tried to partition the SD card with FDISK80:

B>fdisk80

FDISK80 for RomWBW, UNA, Mini-M68k, KISS-68030, SBC-188  ----  

       Version 1.1-23 created 3-June-2023

                 (Running under RomWBW HBIOS)

HBIOS unit number [0..2]: 2

Capacity of disk 2:  ( 14G)  30367744      Geom cf601010

Nr  ---Type- A --      Start         End   LBA start  LBA count  Size

 1 FAT32 lba   0c    260:0:1  1023:15:16       66560   30301184   14G

 2             00       *** empty ***

 3             00       *** empty ***

 4             00       *** empty ***

   Reserved 4 x 8Mb CP/M slices

>>I

>>R

Reserve how many CP/M slices (256 max.) [8]: 4

4 CP/M slices have been reserved

>>N

New partition number: 1

Starting Cylinder (default 260): 

Ending Cylinder (or Size= "+nnn"): +500M

>>t

Change type of partition number: 1

New type (in hex), "L" lists types: 0b

>>p

Nr  ---Type- A --      Start         End   LBA start  LBA count  Size

 1     FAT32   0b    260:0:1  1023:15:16       66560   30301184   14G

 2             00       *** empty ***

 3             00       *** empty ***

 4             00       *** empty ***

   Reserved 4 x 8Mb CP/M slices

>>W

Do you really want to write to disk? [N/y]: Y

Okay

FDISK exit.

After a reboot subsequently initializing CP/M drives C:, D:, E: and F: with CLRDIR C: -Y etc.

Unfortunately the issue begins with:

B>pip c:=b:stat.com[v]

VERIFY ERROR: =B:STAT.COM[V]

 

It looks like that slice/drive C: is pointing to somewhere undefined. Drives D: etc. procedure the same error. Omitting the verification results in an unusable file although the size information is correct.

Changing the SD card with an alternative one brings up the same problem.

As the documentation is quite clear and I didn't found any similar posts in this forum I'm obviously doing something wrong. But what?

Any help appreciated!

Thanks,

Marc

[Doug Jackson]

You may need to do a CLRDIR C: to get the directory ready for files.

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[Wayne Warthen]

Hi Marc,

I don't see anything wrong with the procedure you are using.  I ran through the same steps and it seemed to work fine -- see below.

Since you have tried multiple SD Cards already, I am very surprised by this problem.  It might be worth trying the approach of initializing the SD Card by writing it with one of the pre-built images such as "hd1k-combo.img".  It you can boot to a disk OS this way, then try reading/writing files.

Thanks, Wayne

RomWBW HBIOS v3.5.1, 2025-05-21

Small Computer SC131 [SCZ180_sc131_std] Z8S180-N @ 18.432MHz IO=0xC0
0 MEM W/S, 2 I/O W/S, INT MODE 2, Z180 MMU
512KB ROM, 512KB RAM, HEAP=0x4E3F
ROM VERIFY: 00 00 00 00 PASS

ASCI0: IO=0xC0 ASCI W/BRG MODE=115200,8,N,1
ASCI1: IO=0xC1 ASCI W/BRG MODE=115200,8,N,1
INTRTC: Wed 2020-01-01 00:00:00
MD: UNITS=2 ROMDISK=384KB RAMDISK=256KB
SD: MODE=SC OPR=0x0C CNTR=0xCA TRDR=0xCB DEVICES=1
SD0: SDXC NAME=SL64G BLOCKS=0x076F5000 SIZE=60906MB

Unit        Device      Type              Capacity/Mode
----------  ----------  ----------------  --------------------
Char 0      ASCI0:      RS-232            115200,8,N,1
Char 1      ASCI1:      RS-232            115200,8,N,1
Disk 0      MD0:        RAM Disk          256KB,LBA
Disk 1      MD1:        ROM Disk          384KB,LBA
Disk 2      SD0:        SD Card           60906MB,LBA


Small Computer SC131 [SCZ180_sc131_std] Boot Loader

Boot [H=Help]: c

Loading CP/M 2.2...

CBIOS v3.5.1 [WBW]

Configuring Drives...

        A:=MD0:0
        B:=MD1:0
        C:=SD0:0
        D:=SD0:1
        E:=SD0:2
        F:=SD0:3
        G:=SD0:4
        H:=SD0:5
        I:=SD0:6
        J:=SD0:7

        1859 Disk Buffer Bytes Free

CP/M-80 v2.2, 54.0K TPA

B>fdisk80


FDISK80 for RomWBW, UNA, Mini-M68k, KISS-68030, SBC-188  ----
       Version 1.1-23 created 3-June-2023
                 (Running under RomWBW HBIOS)

HBIOS unit number [0..2]: 2

Capacity of disk 2:  ( 59G)  124735488      Geom 6f501010

Nr  ---Type- A --      Start         End   LBA start  LBA count  Size

 1     FAT32   0b    260:0:1  1023:15:16       66560  124668928   59G

 2             00       *** empty ***
 3             00       *** empty ***
 4             00       *** empty ***
   Reserved 4 x 8Mb CP/M slices

>>i
>>r

Reserve how many CP/M slices (256 max.) [8]: 4
4 CP/M slices have been reserved

>>n

New partition number: 1
Starting Cylinder (default 260):
Ending Cylinder (or Size= "+nnn"): +500M
>>t
Change type of partition number: 1
New type (in hex), "L" lists types: 0b
>>p
Nr  ---Type- A --      Start         End   LBA start  LBA count  Size

 1     FAT32   0b    260:0:1  1023:15:16       66560  124668928   59G

 2             00       *** empty ***
 3             00       *** empty ***
 4             00       *** empty ***
   Reserved 4 x 8Mb CP/M slices

>>w
Do you really want to write to disk? [N/y]: y
Okay
FDISK exit.


B>^C
B>clrdir c: -y
CLRDIR Version 1.2b May 2024 by Max Scane

Directory cleared.
B>clrdir d: -y
CLRDIR Version 1.2b May 2024 by Max Scane

Directory cleared.
B>clrdir e: -y
CLRDIR Version 1.2b May 2024 by Max Scane

Directory cleared.
B>clrdir f: -y
CLRDIR Version 1.2b May 2024 by Max Scane

Directory cleared.

B>pip c:=b:stat.com[v]

B>dir c:
C: STAT     COM
B>c:stat
A: R/W, Space: 248k
B: R/W, Space: 22k
C: R/W, Space: 8168k


B>

[MarcK]

Hello Wayne,

Thank you for your response!

As building the SC131 requires bending and cutting the pins of the SD card module I guess this is a likely source of error. I have ordered a replacement and will report back my findings.

Thanks,

Marc

Op donderdag 18 december 2025 om 20:52:07 UTC+1 schreef Wayne Warthen:

[Mark Pruden]

Hi Marc

Since you are new to this, you might want to consider using the Modern hd1k hard disk layout, it has several advantages over the classic layout, and is generally considered the better, unless you have a specific reason of course.

Also is there a reason for reserving only 4 slices (32mb), this is not very many and quite limiting. Also anything less than 8 is problematic as (by default) RomWBW will assign the first 8 slices at startup. The combo images reserve 512mb (64 slices) that is considered a good amount for a 1gb card.

It would be useful for you to post the complete startup messages including the boot of CPM, this might help understand any issues. Another useful command is `assign` for listing the drive mappings, which potentially could be part of the issue.

Mark.