Dobbertin Harddisc

Dobbertin Logo

A harddisc manufactured by the German company Dobbertin.

One of the first ways to connect a Harddisc to the CPC. The Dobbertin harddisc has a capacity of 20 MB. The disc was partitioned in four partitions of 5152 KB each. It was delivered with drivers for CP/M (2.2 and CP/M+) and allows up to 512 directory entries for each partition (including date and time stamps under CP/M Plus).

Reviewed in Amstrad Computer User.

Pictures

• Dobbertin 20 Mb Harddisc
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  Dobbertin 20 Mb Harddisc

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  Dobbertin 20 Mb Harddisc interface

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  Interface Top

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  Interface Bottom

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  Interface PCB Top

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  Interface PCB Bottom

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  Inside 1

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  Inside 2

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  Inside 3: PSU

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  Inside 4: XT controller

Disc

• Dobbertin HD Interface Driver Disc
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  Driver disc side A

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  Driver disc side B

• Dobbertin HD Interface Driver disc (zipped .DSK files)

Software using the Dobbertin Harddrive

• Cosmos
• Dobbertin CP/M Plus
• FutureOS using all four partitions (I, J, K and L)
• Prowort via using Dobbertin CP/M Plus (partitions D, E, F and G)
• X-DDOS (v2.10)

• In addition a lot of (cracked) games are able to run from the HD-20 hard disc

Technical

Uses XD-DOS v2.10 (which supports the harddisc, and additionally supports external double sided 80 track disc drives). The 20 MB harddisc is split into four partitions, with drive names D, E, F, and G (drive name C isn't used here, but may be used as RAM disc, in combination with Dobbertin RAM expansion). Under FutureOS the four partitions are named I, J, K and L. The hard disc is controlled by this I/O Ports:

 #FBE0  Dobbertin Harddisc Data Port
 #FBE1  Dobbertin Harddisc Status, Reset
 #FBE2  Dobbertin Harddisc Select, Configuration
 #FBE3  Dobbertin Harddisc DMA, Interrupt
 #FBE4  Dobbertin Harddisc Reset

The hard drive interface is an PC-XT compatible hard disc interface. The CPC's port mappings are close to the PC-XT's port mappings.

The following information was obtained from Linux/drivers/block/xd.h and MESS pc_hdc.c.

Commands (incomplete list):

CMD_TESTREADY   0x00     test drive ready
CMD_RECALIBRATE 0x01     recalibrate drive
CMD_SENSE       0x03     request sense
CMD_FORMATDRV   0x04    format drive
CMD_VERIFY      0x05     read verify
CMD_FORMATTRK   0x06     format track
CMD_FORMATBAD   0x07     format bad track
CMD_READ        0x08     read
CMD_WRITE       0x0A     write
CMD_SEEK        0x0B     seek

Status (obtained when reading status register):

STAT_READY      0x01    controller is ready 
STAT_INPUT      0x02     data flowing from controller to host 
STAT_COMMAND    0x04    controller in command phase 
STAT_SELECT     0x08     controller is selected 
STAT_REQUEST    0x10     controller requesting data 
STAT_INTERRUPT  0x20     controller requesting interrupt

Other harddisc solutions for the CPC

• Vortex Winchester Drive (MFM)

Modern:

• CPC-IDE (IDE)
• HDCPC (IDE)
• IDE8255 (IDE)
• SYMBiFACE II (IDE)

Promo (summary) (english)

• Controller: Seagate ST11M XT-controler.
• Harddisc: 20 MB (3.5" Seagate, NEC, Kyocera, or Miniscribe)
• X-DDOS 2.10 (selectable in ROM bank 1-7)
• 4 Partitions of 5152 KB (5 MB) (accessible as Drive D: to G:)
• 512 Directory entries per partition
• support for CP/M 2.2 with 63K TPA (requires 128 KB RAM), and for CP/M Plus
• support for Softwareclock and TIMEROM+ (Real Time Clock under CP/M Plus)
• Price: DM 1100.-

Promo (german)

• Dobbertin Festplatte
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  Frontpage

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  Contents

Downloads

• GAL16V8_IC6 (.JED File)
• GAL16V8_IC11 (.JED File)