[[Image:Dobbertin.gif|thumb|Dobbertin Logo]]
A harddisc manufactured by the German company [[Dobbertin|Dobbertin Industrie-Elektronik]].
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).
It's even possible to boot CP/M Plus from the hard disc.
<gallery caption="Dobbertin 20 Mb Harddisc">
Image:Dobbertin 20 Mb Harddisc.JPG|Dobbertin 20 Mb Harddisc
Image:Dobbertin 20 Mb Harddisc interface.JPG|Dobbertin 20 Mb Harddisc interface
Image:DobbertinHDInterface_Top.jpg|Interface Top
Image:DobbertinHDInterface_Bottom.jpg|Interface Bottom
Image:DobbertinHDInterface_PCB_Top.jpg|Interface PCB Top
Image:DobbertinHDInterface_PCB_Bottom.jpg|Interface PCB Bottom
Image:Dobbertin 20 Mb Harddisc.JPG|Dobbertin 20 Mb Harddisc
Image:Dobbertin 20 Mb Harddisc interface.JPG|Dobbertin 20 Mb Harddisc interface
Image:Dobbertin 20 Mb Harddisc inside 1.JPG|Inside 1
Image:Dobbertin 20 Mb Harddisc inside 2.JPG|Inside 2
Image:Dobbertin 20 Mb Harddisc inside 3.JPG|Inside 3: PSU
Image:Dobbertin 20 Mb Harddisc inside 4.JPG|Inside 4: XT controller
</gallery>
<gallery caption="Thanks to Jose Leandro - Interface PCB Layouts">
Image:Interface PCB Front.png|Interface PCB Front
Image:Interface PCB Front.JPG|Interface PCB Front
Image:Interface PCB Back.png|Interface PCB Back
Image:Interface PCB Back.JPG|Interface PCB Back
Image:Interface PCB Layout.jpg|Interface PCB Layout
</gallery>
<gallery caption="Thanks to Jose Leandro - Internal PCB Layouts">
Image:Internal PCB Front.png|Internal PCB Front
Image:Internal PCB Front.JPG|Internal PCB Front
Image:Internal PCB Back.png|Internal PCB Back
Image:Internal PCB Back.JPG|Internal PCB Back
Image:Internal PCB Layout.png|Internal PCB Layout
</gallery>
</gallery>
<br>
* [[Media:DobbertinHDInterface_Disk.zip|Dobbertin HD Interface Driver disc]] (zipped .DSK files)
== Software using the Dobbertin Harddrive ==
*[[Cosmos]]
*Dobbertin CP/M 2.2 (63 KB TPA) and CP/M Plus
*[[FutureOS|FutureOS]] using all four partitions (I, J, K and L)
*[[Maxam_2|MAXAM II]]
*[[Prowort]] via using Dobbertin CP/M Plus (partitions D, E, F and G)
*[[X-DDOS|X-DDOS]] (v2.10)
*[[Z3Plus]] and [[NZ-COM]] (providing hundreds of additional applications)*'-HD20BackUp' to backup / compare / restore the complete 20 MB hard disc* 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 Dobbertin HD20 is a hard disk that has an interface that appears to implement 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 SASI protocol (drive name C isn't used here, but may be used as RAM disc, in combination with Dobbertin RAM expansionShugart Associates System Interface). 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 (A precursor to the PC-XT's port mappingsSCSI) but which has registers which look similar to those of the OMTI 5510.
(The following information was obtained from Linux/drivers/block/xd.h and MESS pc_hdc.cSASI protocol is also used by the SA1000).
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 seekThe controller is a Seagate ST-11M.
Status (obtained when reading status register):There is an expansion port interface which connects to the CPC.
STAT_READY 0x01 controller It contains a 16KB ROM containing [[X-DDOS]] which is ready normally in slot 6 but can be configured between 1 and 7. STAT_INPUT 0x02 data flowing from controller There is a CPC interface which connects to host a PC-XT interface. STAT_COMMAND 0x04 controller The OMTI 5510 appears to be very close in terms of operation and commands, but the Dobbertin is probably not this. The command phase descriptions and operation appear to be the same although the software seems to only use TEST READY, READ, WRITE, SEEK (parking), SET PARAMETERS and FORMAT. Uses [[X-DDOS]] v2.10 (which supports the 20 MB hard-disc, and additionally supports external double sided 80 track disc drives). The 20 MB hard-disc 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. They can be accessed at the same time, so all 20 MB are usable at the same time. The hard disc is controlled by this I/O Ports: #FBE0 Dobbertin Harddisc Data Port (read/write) #FBE1 Dobbertin Harddisc Status (read), Reset (write) #FBE2 Dobbertin Harddisc Select (write), Configuration (read) #FBE3 Dobbertin Harddisc DMA, Interrupt (Used on CPC???) #FBE4-FBE7 Dobbertin Harddisc Reset (read or write will reset) Port decoding: A15-A10, A8-A7 are decoded by U11. A4,A3 from U9B. STAT_SELECT 0x08 controller A9 is selected G1, A2 = A, A5 = B, A6 = C into U10 STAT_REQUEST 0x10 controller requesting data A1,A0 are used when I/O range FBE0-FBE3. STAT_INTERRUPT R/W are used. 0x20 controller requesting Data is used by device. FBE0-FBE3 are decoded as 111110111110000rr R/W not used, so read and write will access this port. Data is not important. FBE4 is decoded as 111110111110001xx Therefore FBE4-FBE7 access the same port. There is additional port decoding which appears to force bus value with some I/O reads, interruptrequest, rom read and ram read. The purpose is not clear. 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. To format the hard disk you need to use the CPM based system tools. To use the tools you need to patch a CPM+ disc so that it recognises the hard disk. * CPM/AMSDOS format* 512 bytes per sector (possibly defined with jumpers)* 17 sectors per cylinder (possibly defined with jumpers)* &E5 format filler byte* 4 heads (maybe configured by X-DDOS)* 614 cylinders (maybe configured by X-DDOS) TFM's comment: For FutureOS I researched this hard-disc and I found 17 sectors of 512 bytes per track. It has four heads and 615 cylinders. For optimum speed the sectors and tracks have to be read / written in a defined sequence to reach maximum data transfer speed (about 80 kb/sec). It's not the case that number of sectors, heads, tracks etc. can be redefined (neither software, nor jumpers). These are real hardware values! == Emulation ==The Dobbertin HD20 is emulated by the Symbiface III since 7/2023. Therefore you need a subfolder 'HD20' on the USB stick. It needs to contain the 21 MB hard-disc image file. It is also [https://www.cpcwiki.eu/forum/emulators/got-bored-again/ emulated in MAME since 6/2015]
== Other harddisc solutions for the CPC ==
Modern:
* [[Albireo]] (SD card)
* [[CPC-IDE]] (IDE)
* [[HDCPC]] (IDE)
* [[IDE8255]] (IDE)
* [[M4 Board]] (SD card)
* [[SYMBiFACE II]] (IDE)
* [[SYMBiFACE III]] (USB, SD card)
* [[X-MASS]] (IDE)
== Promo (summary) (english) ==
* 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.-(approx. 562 Euros)
== Promo (germanGerman) ==
<gallery caption="Dobbertin Festplatte">
Image:Dobbertin festplatte page1.jpg|Frontpage
Image:Dobbertin festplatte page2.jpg|Contents
</gallery>
== Downloads ==
* [[Media:DobbertinHD_GAL16V8_IC6Layouts on Eagle.JEDzip|GAL16V8_IC6Layouts on Eagle.zip]] (* [[Media:GALs.JED File)zip|GALs.zip]]* [[Media:DobbertinHD_GAL16V8_IC11DobbertinHDInterface_Disk.JEDzip|GAL16V8_IC11Dobbertin HD Interface Driver disc.zip]] == Links == * ftp://ftp.seagate.com/techsuppt/controllers/st11m-r.txt* http://hardware.speccy.org/temp/Amstrad-DiscoDuro.html* http://heathkit.garlanger.com/companies/ShugartAssociates/sasi_r0a.pdf* WD1002-SHD datasheet (fewer commands, similar to commands used by Dobbertin)* http://bitsavers.JED Filetrailing-edge.com/pdf/sms/pc/OMTI_5510_Winchester_Controller_Jun85.pdf (more commands, similar to Dobbertin in registers and commands)* https://www.lo-tech.co.uk/w/index.php?title=Seagate_ST11M_Installation_Guide&oldid=480
[[Category:PeripheralsDATA Storage]][[Category:DATA StorageFutureOS]] [[Category:Peripherals]]