Data General MTB Reference Sought

[Bruce Ray]

In most tape devices the DCH Device address register refers to a logical 
address - 0-32 KWords in Novas and Eclipses, and usually 0-256KB in most 
MVs.  In a mapped system, DCH map functions are transparent to these 
devices since only the 'logical' address is sent from the device to the 
CPU during a DCH data transfer.  It is up to the specific processor and 
its corresponding operating system to determine how and when the 
logical-to-physical map.  The DG hardware interface guide describes the 
PIO, DCH and on MVs the BMC, specifications.


On 2/23/2017 12:32 AM, Stephen Merrony wrote:
> Hi Bruce,
>
> Thanks for that confirmation of my hazy memory!
>
> What I can't seem to find is any reference as to how the tape drives interact with the DCH bus and the associated map slots.  I thought maybe a later guide might cover that?
>
> Steve
>
> -----Original Message-----
> From: Bruce Ray [mailto:Bruce at Wild-Hare.com]
> Sent: 25 January 2017 18:23
> To: General Discussion: On-Topic Posts <cctech at classiccmp.org>
> Subject: Re: Data General MTB Reference Sought
>
> G'day Steve -
>
> AOS/VS OS tape drive base names are MTA, MTB, MTC, etc. and do not directly correspond to the assembler mnemonic name(s) - don't be confused by this difference.
>
> The AOS/VS 'MTA'-type tape drive is described on page IV-5.  These correspond to the original DG model 4030/6020 units.
>
> The AOS/VS 'MTB'-type tape drive is described on page IV-15. These correspond to the DG model 6026 units.
>
> The AOS/VS 'MTC'-type tape drive is internally the same as the MTB except only a single unit is supported.  This was done to distinguish single-unit support for the popular DG model 6125 streamer.
>
> The IV-15 mag tape programming model was consistent between the Nova/Eclipse/MV bus controllers and the Lbus controllers through emulation.  One size [almost] fit all.
>
> What difference(s) are you seeing?
>
>
> Bruce
>
>
>
> On 1/25/2017 1:01 AM, Stephen Merrony wrote:
>> Does anyone have (a scan of) a manual that covers programming the
>> MV-era MTB tape controller?
>>
>> I have a 1980 "Peripherals" manual (014-000632-01) from the
>> "Programmer's Reference Series" which covers the MTA type, but it
>> seems that the MTB behaves a bit differently and I am missing some
>> information for my current project.
>>
>> Thanks,
>>
>> Steve
>>
>
>