A/The Sun SparcStation 4/TCX-Framebuffer mini-FAQ

From: Eric Berggren (eric@ee.pdx.edu)
Date: Wed May 10 1995 - 12:22:08 CDT

  [I'm posting this to several newsgroups to address people in
   different areas. My apologies to those who see this more than

  I humbly present this mini-FAQ regarding Sun's new line of
low-cost/end workstations, the SparcStation 4, and the new TCX
graphics framebuffer that's associated with it. It is addressed to
those who are considering or have recently purchased one or more of
them, or those who are just plain curious. They were found to be
unsuitable to our environment, but may work quite well for others. I
am therefore being (mostly) objective about this presentation. This
mini-FAQ is dated May 10th, 1995 with the latest information available
to me (but I doubt is likely to change in the very near future). It is
derived from our experiences and exchanges with regional area Sun
Microsystems SE's (ie, I do not represent Sun); I also grabbed some
numbers from Vikas Jha's article floating around usenet during this
time (Subject: _SS5 vs. SS4 (esp. graphics performance)_). This is a
one-time effort for me with no intention of further verifying/updating
this information with reasons explained below.

  We shall begin....


        1 - What is the SparcStation 4 ?
        2 - What is the TCX framebuffer ?
        3 - Will SunOS 4 run on the SparcStation 4 ?
        4 - How is the performance of the TCX rate to other framebuffers ?
        5 - Will the MIT X server run under the SparcStation 4 ?
        6 - Will "Doom" run on the SparcStation 4 ?


  1: What is the SparcStation 4 ?

     In short, it is Sun's new line of low-cost/end workstations. It is
     modeled after the SparcStation 5 (same architecture), with slight
     performance improvements (see below) but sporting only a single
     Sbus slot and a special port for an optional 16-bit audio
     controller (using the same CS4231 chipset found on the SS5). With
     a 20" monitor (well, Sun's definition of 20"), it was priced
     a couple hundred dollars cheaper than the SS5 (even after adding
     in the audio controller) making it a seemingly attractive line.


     Performance numbers from SUN:

                             SS4/70 SS5/70

     (1).SPECint92 59.6 59.6
     (2).SPECfp92 46.8 46.8
     (3).SPECrate_int92 1414 1352
     (4).SPECrate_fp92 1100 1122
     (5).MIPS 105.4 100.3
     (6).MFLOPS 15.8 13.1

     [mileage may vary above; best to assume them being equal]

                             SS4/70 SS5/70

     (1).MainMemory: 16-160M 16-256M
     (2).Max: 535M(*) 2.1G
     (3).Max.Ext.disk: 28G 56G
     (4).Packageslots: 1 SBus conn. 3 SBus connectors
     (5).Serialports: 1 sync 1 async 2 synchronous
     (5).Audio 16bit(optional) 16bit

     [the cabinet in the SS4 is almost identical to that of the SS5,
      with four drive bays (incl floppy/cdrom); however, in the SS4,
      the one harddrive sits immediately above the motherboard with
      no connector plane for the other 2 bays; one could always hack,
      i suppose.

      i'm sure a larger drive could be used, with the correct
      formfactor. ]

  2: What is the TCX framebuffer ?

     The "TCX" is the standard 8-bit graphics controller hardware
     that is built-in to the SS4 motherboard. By default, it runs
     in the standard 1152x900 resolution mode, but can be expanded
     to support 1280x1024 resolution by adding VSIMM memory to the
     special socket on the motherboard, alledgedly with no performance
     degradation. Summarized below :

                     SS4 SS5

     graph. 8-bit pixel-accelerated (i) Turbo GX 8-bit
             1152x900 res standard (8bit 2-D/3-D wireframe,
             1280x1024 res optional 1152 x 900).
             (video memory expansion
             SIMM required)
                                     (ii) Turbo GX 8-bit plus
                                          (8bit 2-D/3-D wireframe,
                                          1152 x 900 or 1280 x 1024,
                                          double buffering).
                                     (iii)24-bit true color graphics,
                                          1152 x 900.

     Pixel Accelerator [sun]

     o Feature o Benefit

       - On-board pixel accelerator - Speeds screen functions: fills,
                                               text, and scrolling
                                             - More than twice the screen
                                               performance of the CG3 frame
                                               buffer used in the SPARCclassic
       - 1280 x 1024 video memory expansion - Tailors the system to apps
                                               supporting high resolutions
                                             - No degradation in performance
                                             - Low cost

       - Fast video memory interface - Further speeds execution of
                                               screen functions

       - State-less, single-instruction - Limits graphics circuitry for
         architecture high performance at a low cost

     The capabilities of the TCX are only accessible under Solaris 2 (2.4+),
     however. This is a new frame buffer that will not be recognized by
     current applications that directly access the graphics hardware. THIS
     INCLUDES THE STOCK MIT X SERVER. [there is no plans at this time from
     the X consortium to expand support for the TCX]. Another interesting
     note regarding performance from an SE, "(Even when fully-exploited,
     this device's performance will generally not equal that of higher-end
     accelerators such as the TGX/TGX+ - particularly for vector-intensive

     Running Solaris 1.1.2 (SunOS 4.1.4), "this display presents itself as
     a "CG3"-type device - an unaccelerated 8-bit frame buffer." [sun].
     This is the same controller used by the SparcClassic systems and
     in typical color IPC configurations. For comparison, the
     performance resembles a Tektronix XP18 color X terminal and not
     far off from a Sun 3/50 running Xkernel. This is the case running
     either X or OpenWindows.

  3: Will SunOS 4 run on the SparcStation 4 ?

     SunOS 4 will run on the SS4, but you MUST run SunOS 4.1.4 .
     Earlier versions, including SunOS 4.1.3_U1, will NOT support the
     new framebuffer.

     Note: there is a caveat running SunOS 4 in that it will only
           support the TCX running as a CG3 (unaccelarated). (See #2)

  4: How is the performance of the TCX rate to other framebuffers ?

     I do not have any actual numbers but performance will vary depending
     on the type of application, and whether you run SunOS 4.1.4 or
     Solaris 2 (see #2). The following is quoted from an (unnamed)
     Sun SE:

         The SPARCstation 4 built-in display is a low-cost 8-bit
         frame buffer with hardware support for a class of common
         windowing operations including text, fills, stipples, and
         scrolling/"blit"ing. The capabilities of this display are
         fully exploited by Solaris 2.4 and its X server (Xsun).
         (Even when fully-exploited, this device's performance will
         generally not equal that of higher-end accelerators such as
         the TGX/TGX+ - particularly for vector-intensive rendering.)

  5: Will my MIT X server run under the SparcStation 4 ?

     The short, direct answer is "NO", the MIT X window server does not
     support the TCX framebuffer, with no indication at this point from
     the X consortium that it will be supported anywhere in the near
     future (partly due to non-disclosure of the TCX intrinsics).

     There is an exception to this, however. Since under SunOS 4.1.4,
     the driver will driver the framebuffer as a CG3, which *is*
     supported by the MIT X server, one can therefore run the server
     on an SS4 under SunOS 4. The R5 server requires the JPL "multiscreen"
     patch to work properly (see #80 in the X FAQ found in the usenet
     newsgroup, comp.windows.x for availability info; also found via
     ftp:ftp.x.org/R5contrib/Xsun.multi-screen). As reported by Sun :

         All the "R5.Xsun.multi-screen" patches do is clean up
         Xsun's initialization code so that it recognizes that
         "/dev/fb" is a "CG3"-type device and it can use its
         "CG3" ddx code to drive it. This improved initialization
         code is included in R6 (no patch necessary).

     I have not actually tried R6 under SunOS 4 to validate this.
     This route will NOT work under Solaris 2.4, since the driver
     does not present a "CG3" :

         The patch doesn't add Solaris 2.X native TCX support.
         R6 doesn't have Solaris 2.X native TCX support. Solaris
         2.4 doesn't provide CG3 emulation of TCX (doesn't need it).

     Customers will be expected to simply run the OpenWindows server
     under Solaris 2 to get the performance and applications they need:

         The MIT sample server is just not always going to be an
         option. That's why vendors ship X server products. If you
         want to get a feel for what the full performance of this
         display device is, just run the Solaris 2.4 X server (Xsun).
         It's very standard and very directly based on MIT X11R5 -
         with the added value of *full* support for the range of Sun
         display devices including that of the SS4 (not to mention QA,
         vendor support, Display PostScript, etc.).

     And for those adventurous to want to write their own drivers, our
     response was simply, "The low-level display hardware programming
     interfaces are not public."

     I'll let this sit as is....

  6: Will "Doom" run on the SparcStation 4 ?

     The all important question. Running Solaris 2.4 with the audiocs
     patch (102125-01) [rev 02 is now available] and OpenWindows, the
     X version of "Doom" was able to run with good performance. The
     "DGA" version, however, dumped core for us (as though it was
     running under a straight X server). I'll leave this to someone
     else to file a service order.


  Regrettably, our labs are still running SunOS 4, given that alot of
  software won't run and/or is not presently available for Solaris 2.
  We also run the MIT X server under both SunOS 4 [R5] and Solaris 2
  [R6] as numerous software that we have deployed do not properly work
  under OpenWindows (either 3.0 or 3.4, the X11R5 based server). We
  will subsequently be returning our entire lot [15+] (and thus, I
  won't be tracking progress on future SS4 developments).

  I realize changes are often necessary, but I would advise Sun to take
  a lighter attitude towards simply expecting customers to adopt their
  applications/work-environments just to make any use of new hardware,
  as this is not always practical or feasible for those customers. We
  also ran into major mis-communications (or lack of) regarding new
  products and local representatives who deal directly with customers.
  Having this improved would save many people time and headaches with
  this information available up front.

  I have concluded....


  Eric Berggren             | "Parts of this product may be derived from
  Portland State University |  from UNIX and Berkeley 4.3 BSD systems..."
  eric@ee.pdx.edu           |                  -- Label on Solaris 2.x disk

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