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/* Technical */
== Technical ==
Dobbertin HD20 is a relative of the Winchester type hard disk.There is a CPC interface which connects to a PC-XT interface.
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(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 Dobbertin Harddisc Reset(read or write will reset) (Exact port decodings to be confirmed; the GALs probably describe it)
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.
