From: nathan@laplace.biology.yale.edu (Nathan F. Janette)
Subject: NeXT-FAQ.internal: Questions about NeXT internal hardware
Reply-To: nathan@laplace.biology.yale.edu
Organization: Yale University, Department of Computer Science, New Haven, CT
Date: Thu, 23 Jul 1992 21:47:18 GMT
Expires: Fri, 28 Aug 1992 00:00:00 GMT

NeXT-FAQ.internal: Questions about NeXT internal hardware


*** Subject: I1. What can be done about older 030 NeXT cubes that have a fan  
that turns in the "wrong" direction?

The fan on older 030 NeXTs cubes sucks air out of the back of
the cube  which means that it draws unfiltered air in
through the optical disk on the front of the cube.  This
causes optical disks to succumb to dust must sooner than
cubes with the new-style fan which turns in the opposite
direction.

NeXT has apparently reversed their decision regarding
fan reversal in the case of machines that have been
upgraded to 040 processor boards.  It is now considered
okay to reverse the direction of fans in these machines. 
If you have many third-party cards installed in your cube
or an older processor board, you may wish  to consider not
reversing fan direction (overheating could become  a
problem).  In any case, do not reverse the fan's polarity,
only reverse the fan assembly itself.  Perhaps the best
solution is  obtain the cleaning kit and OD filter from
NeXT. 


*** Subject: I2. Can I connect SONY MPX-111N to my 030 cube?

The SONY MPX-111N internal 2.88 MB floppy drive which is
shipped with all the new 040 NeXT machines is *not* a SCSI
device, therefor there is no way of connecting that
particular drive internally on an 030 system. 


*** Subject: I3. Why does the OD continually spins up and spins down?

A big problem with the Cannon optical drives is that air
flows through the drive to cool it.  Dust accumulates
inside the drive causing it to fail with the continuous
spin-up spin-down syndrome.  NeXT as part of it's 040
upgrades provides a dust filter to prevent this.  If your
drive has this problem it usually can be fixed simply by
cleaning out dust from the drive.  NeXT sells a cleaning
kit for both the drives and the optical disks. 


*** Subject: I4. How many colors can NeXT machines display?

The monochrome machines can display 4 gray levels.  You
can use color apps on a monochrome machine,  they will
converted into monochrome images and dithered
accordingly.

Color NeXTstations can combine 4 bits of red, green and
blue primaries for a total of 4096 "pure" colors.  The
imaging functions dither the image to produce
intermediate colors.

NeXTdimension can combine 8 bits of red, green and blue
for 16,777,216.  There are not 16 million points on the
display so all can not be displayed at once.  Further
display technology limits the usable color space.

None of the NeXT products support color look up tables
where the user can define their own color palette on a per
window basis. This feature is useful for displaying
images which have adaptive lookup tables, and display
pure grayscale images on the color NeXTstation.  On the
NeXTdimension images can be converted to full 24 bit
representation. 


*** Subject: I5. Why is my machine so slow when I run the monochrome and  
NeXTdimension displays?

There is a bug with the window system in which if you select
the monochrome display as your primary display the
server will be much much slower.  The solution for those
wishing to use both displays is to select the color
(NeXTdimension) display as the primary display.  The
most optimal configuration at present with the
NeXTdimension is to run only the color display. 



--
Editor:
Nathan Janette nathan@laplace.csb.yale.edu


--
Nathan Janette		"I'm a NeXTstep man,
Dept MB&B, Yale Univ	 I'm a NeXTcube guy"
New Haven, CT
nathan@laplace.biology.yale.edu (NeXT)

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