Investigating the MV/2500 DC System Disk
The system disk in my MV/2500DC was a DG-ROMmed Micropolis unit. DG were (in)famous for locking-in customers by preventing the use of off-the-shelf peripherals. This disk is a case in point – it cannot simply be replaced by an ostensibly equivalent Micropolis drive.
The purpose of this investigation was to determine the information required to emulate the system disk with a SCSI2SD unit. See Replacing the MV/2500 System Disk for more information on that process.
Physical Characteristics
- Full height, 5.25 inch hard disk.
- MOLEX power connector.
- 50-pin unkeyed full size SCSI socket
Labelling
- M/N 1578
- S/N 9063660101
- P/N DS0052-07-6B
- HDA No.S0531250
- Interface SCSI
- Capacity 382MB
- Copyright 1987 Micropolis
ROM Labelling
- 800278-04-6
- 211B
- 5/5/88
SCSI Characteristics
The SCSI characteristics were explored by connecting the disk to an Adaptec 29160N SCSI board on a PC then querying the drive under both Windows 7 and Ubuntu GNU/Linux.
SCSI Inquiry Result
Using Visual SCSI Explorer under 64-bit Windows 7 Home Premium…
Execute "Inquiry (12h)" command, EVPD 0, page code 0x00 (0), allocation length 0
x00FF (255), CDB length 6, CDB (hex) 12 00 00 00 FF 00
Dump data size 0x00000024 (36) byte(s), dump data (hex):
00000000: 00 4C 01 01 1F 12 00 00 4D 49 43 52 4F 50 20 20 .L......MICROP
00000010: 31 35 37 38 2D 31 35 20 20 20 20 20 20 20 55 50 1578-15 UP
00000020: 44 47 30 32 DG02
Received 36 bytes of inqury data
Peripheral Qualifier 0x0 (0)
Peripheral Device Type 0x0 (0)
Removable Medium (RMB) 0
Device-type Modifier 0x4C (76)
ISO Version 0x0 (0)
ECMA Version 0x0 (0)
ANSI-approved Version 0x1 (1)
Asynchronous Event Notification Capability (AENC) 0
Terminate I/O Process (TrmIOP) 0
Response Data Format 0x1 (1)
Additional Length 0x1F (31)
Relative Addressing (RelAdr) 0
Wide Bus 32 (WBus32) 0
Wide Bus 16 (WBus16) 0
Synchronous Transfer (Sync) 0
Linked Command (Linked) 0
Command Queuing (CmdQue) 0
Soft Reset (SftRe) 0
Vendor Identification: MICROP
Product Identification: 1578-15 UP
Product Revision Level: DG02
"Inquiry (12h)" command completed, adapter status 0 <Success>, SCSI status: 0x00
<Good>, execution time 7947 mcs
In 64-bit Ubuntu GNU/Linux…
root@brahma-lubuntu64:~# sginfo -6 -a -T /dev/sdh
cdb: 12 00 00 00 24 00
INQUIRY response (cmd: 0x12)
----------------------------
Device Type 0
Vendor: MICROP
Product: 1578-15 UP
Revision level: DG02
cdb: 12 01 00 00 04 00
do_scsi_io: opcode=0x12: SCSI status: Check Condition
Fixed format, current; Sense key: Illegal Request
Additional sense: Invalid field in cdb
Sense Key Specific: Error in Command byte 1 bit 0
Raw sense data (in hex):
70 00 05 00 00 00 00 0c 00 00 00 00 24 00 00 c8
00 01 00 17
No serial number (error doing INQUIRY, supported VPDs)
cdb: 1a 00 3f 00 04 00
cdb: 1a 00 3f 00 4c 00
cdb: 1a 00 01 00 04 00
cdb: 1a 00 01 00 14 00
Read-Write Error Recovery mode page (0x1)
-----------------------------------------
AWRE 0
ARRE 0
TB 1
RC 0
EER 0
PER 0
DTE 0
DCR 0
Read Retry Count 10
Correction Span 11
Head Offset Count 0
Data Strobe Offset Count 0
Write Retry Count 45
Recovery Time Limit (ms) 13600
cdb: 1a 00 02 00 04 00
cdb: 1a 00 02 00 18 00
Disconnect-Reconnect mode page (0x2)
------------------------------------
Buffer full ratio 0
Buffer empty ratio 0
Bus Inactivity Limit (SAS: 100us) 5
Disconnect Time Limit 0
Connect Time Limit (SAS: 100us) 0
Maximum Burst Size 0
EMDP 0
Fair Arbitration (fcp:faa,fab,fac) 2
DIMM 0
DTDC 0
First Burst Size 8224
cdb: 1a 00 03 00 04 00
cdb: 1a 00 03 00 24 00
Format Device mode page (0x3)
-----------------------------
Tracks per Zone 1
Alternate sectors per zone 1
Alternate tracks per zone 0
Alternate tracks per lu 45
Sectors per track 36
Data bytes per physical sector 512
Interleave 1
Track skew factor 0
Cylinder skew factor 12
Supports Soft Sectoring 0
Supports Hard Sectoring 1
Removable Medium 0
Surface 0
cdb: 1a 00 04 00 04 00
cdb: 1a 00 04 00 20 00
Rigid Disk Geometry mode page (0x4)
-----------------------------------
Number of cylinders 1224
Number of heads 15
Starting cyl. write precomp 0
Starting cyl. reduced current 0
Device step rate 0
Landing Zone Cylinder 0
RPL 0
Rotational Offset 0
Rotational Rate 16384
SCSI Modes
:~# sg_modes -6 -vvvvv /dev/sdh
found bsg_major=252
open /dev/sdh with flags=0x800
inquiry cdb: 12 00 00 00 24 00
duration=4 ms
MICROP 1578-15 UP DG02 peripheral_type: disk [0x0]
mode sense (6) cdb: 1a 00 3f 00 fc 00
duration=4 ms
mode sense (6): pass-through requested 252 bytes (data-in) but got 76 bytes
mode sense (6): response
4b 00 00 08 00 09 a1 0d 00 00 02 00 81 06 20 0a
0b 00 00 00 82 0a 00 00 00 05 00 00 00 00 00 00
83 16 00 01 00 01 00 00 00 2d 00 24 02 00 00 01
00 00 00 0c 40 00 00 00 84 12 00 04 c8 0f 00 00
00 00 00 00 00 00 00 00 00 00 00 00
Mode parameter header from MODE SENSE(6):
Mode data length=76, medium type=0x00, WP=0, DpoFua=0, longlba=0
Block descriptor length=8
> Direct access device block descriptors:
Density code=0x0
00 00 09 a1 0d 00 00 02 00
>> Read-Write error recovery, page_control: current
00 81 06 20 0a 0b 00 00 00
>> Disconnect-Reconnect, page_control: current
00 82 0a 00 00 00 05 00 00 00 00 00 00
>> Format (obsolete), page_control: current
00 83 16 00 01 00 01 00 00 00 2d 00 24 02
10 00 00 00 0c 40 00 00 00
>> Rigid disk geometry (obsolete), page_control: current
00 84 12 00 04 c8 0f 00 00 00 00 00 00 00
10 00 00 00 00