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From: rwood@vajra.dec.com (Richard Wood)
Newsgroups: comp.sys.dec
Subject: Re: Gray-scale PMAX ????
Message-ID: <686@granite.dec.com>
Date: 18 Nov 89 02:46:10 GMT
References: <15500001@hpdml93.HP.COM>
Sender: news@granite.dec.com
Reply-To: rwood@vajra.dec.com (Richard Wood)
Organization: Digital Equipment Corporation
Lines: 33

In article <15500001@hpdml93.HP.COM>, sritacco@hpdml93.HP.COM (Steve
Ritacco) writes:
> I picked up the technical description of the DECStation 3100 off
> the DEC public FTP server, and after reading it I have a few questions.
> Are the frame buffer boards in the monochrome and color systems the
> same except for the memory chips.  The description of the PCC (programable
> cursor chip) mentions that on a monochrome system that the cursor may have
> gray levels.  Does this mean that the DECStation is capable of gray-scale
> operation?  I guess DEC doesn't sell it that way, but what happens if you
> connect a DEC monochrome monitor to a color system?  Do you get 256 gray
> levels?

The two SIMMS are different.  

The color simm uses 256K x 4 VRAMS, Mono uses 64K x 4.

The drivers are different.  The etch is different.  The concept and
impelementation are
covered and fully disclosed in DIGITAL patent #xxxxxxxx (An easily
upgradable video system).

The PCC conects to the Video DAC and can be programmed with up to 16
grey/color levels.  This
is not exposed through X windows.

You can connect a mono monitor to a color system.  Green goes to mono. 
50 ohm terminators
must be installed on the Red and Blue BNC's.  All 256 levels will be
displayable.

-- ---------------------------------------------------------------------
Richard Wood     Corporate Worksystems Team      Digital Equipment Corp.
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