Note: Most of the information here is taken verbatim or with a few modifications from the Frame Buffer FAQ by David Tong. To view the whole FAQ click here.

The following is some very basic information that most new comers to Sun struggle with.

So what is a frame buffer anyway?

In its simplest meaning, and as far as the Graphics hardware engineers are concerned, a frame buffer is simply that; the video memory that holds the pixels from which the video display (frame) is refreshed. In the early days, Sun provided seperate "Graphics Processor" or "Graphics Accelerator" and "Graphics Buffer" boards - the processor/accelerator was an add-on (sometimes optional) that provided efficient, tuned hardware pipelines to support graphics functions normally done in software, for example shading, Z-buffering, picking and hidden surface removal. Nowadays with ever-improving manufacturing techniques, the two are tightly linked on the same board. Since every graphics device incorporates a frame buffer, but not all have graphics processors, the term "frame buffer" has become synonymous (outside Engineering at least) for a graphics device of any type. It is perhaps better to talk about "dumb" or unaccelerated frame buffers - devices such as the cgthree, which perform no real action other than to provide a video signal to a monitor - and "smart" frame buffers, which include additional hardware and/or microcode to accelerate 2D and 3D graphics, etc. But once again, advancement in technology means that dumb frame buffers are the exception rather than the rule, and hardware acceleration is taken for granted. So applying the rule of common usage, today's definition of a "frame buffer" is a graphics output device that provides accelerated 2D or 3D graphics, and a "dumb frame buffer" is a graphics output device that does not provide any acceleration. As an aside, the PC world tends to refer to graphics devices as "video cards". In the workstation world, a Video card implies full-motion video, either in (as with Sun's VideoPix or SunVideo products) or out (as in Parallax's XVideo products).

What's the story on PCI?

PCI is a platform independent hardware standard; for details visit the PCI Special Interest Group at http://www.pcisig.com. The intention is that future machines will be developed with PCI interfaces only. However this doesn't mean that SBus is going away - there is still a massive installed base which will be supported for many years to come.

The first PCI frame buffer from Sun is the PGX. This is an 8 bit device with features and performance comparable to the TGX. It supports a wide range of resolutions, and is configured using a program called m64config rather than the old prom-value method required by the TGX. Also unlike previous frame buffers it does not use sense codes to determine the resolution.

For full details of PCI cards that are supported in the Ultra 30 series, including graphics and other products, see http://www.sun.com/pci.

So can I take a PCI card from my Sun and plug it in my PC (or vice-versa)?

As stated above, PCI is a HARDWARE standard. This doesn't mean that you can buy an Ultra 30 and plug in the video card from your PC; Nor can you take a PGX or other PCI card developed for an UltraSparc machine and plug it into a PC and expect it to work. Although the physical connections may be the same the Sun will require different device drivers and on-board firmware.

Having said that, I know of people who have developed basic drivers for PC cards, notably the Matrox Milennium II. And before anyone asks, they are not available for download. Because the card doesn't have OBP (Open Boot Prom) firmware it cannot be used as a console device, only as a second head, and without further information from the manufacturer it isn't possible to enable the advanced acceleration features.

Can I use a PC monitor on an Ultra 5 or Ultra 10?

Any PC monitor that is "Plug And Play" should work with the PGX. Older multisync monitors that do not support "Plug and Play" can be used, but it may be necessary to reconfigure the card manually using m64config, since the default resolution (1152x900) may not be supported by a PC SVGA Monitor and the PGX does not support the "setenv output-device" EPROM command.

Introduce me to Sun's frame buffers.

Note: This section does not deal with the older VME bus frame buffers.

bwtwo

The bwtwo was the monochrome frame buffer found in the old Sun3 machines (remember those?). It was also available as an SBus card for Sparc machines up to the SS20. The MG1 (Monochrome Graphics) was capable of driving a high resolution (1600x1280) display, and looks similar to a cgthree.

MG1 bwtwo with D type connector
MG2 bwtwo with 13W3 connector

cgthree

  When this document talks about the cgthree it refers to an un-accelerated 8 bit SBus frame buffer. It is recognisable by a row of 8 SIL chips (Single In Line) which provide the Video memory and look rather like a heatsink.

The cgthree was built onto the motherboard of some entry level machines.

cgthree with 13W3 connector
cgthree with 13W3 connector. Distinguishable from 501-1415 by having 2 crystals (metal oblongs) instead of 1.

cgsix

Sometimes known as LEGO for Low End Graphics Option, the cgsix family includes the GX, GX+, TGX and TGX+ boards. These are accelerated 2D 8 bit frame buffers. They are the reference point for graphics support, and are supported in all Sparc machines, subject to some restrictions on size and revision; for example the older GX/GX+ cards are not supported in the newest Ultra hardware.

The early GX boards were double-width, as were the GX+ boards. To distinguish the two visually, the double-width GX has several rows (2x16) of SIL chips, whereas the GX+ has convential DIL chips.

The TGX and TGX+ bear a large LSI chip and 8 RAM chips, and have the names of the design team printed above the SBus connector. While there have been at least two versions of the TGX, the chip rev number has not changed. The TGX+ can be distinguished by the characters TGXA printed next to the 13W3 connector, and by having a row of 8 very low profile surface-mounted chips down one side, compared with the larger chips in an L configuration on the TGX and GX.

The TGX/TGX+ are compatible with the GX/GX+ but are faster and support more resolutions. (The T stands for Turbo). The GX/TGX have 1Mb of on-board memory, which gives them a maximum resolution of 1152x900. The GX+/TGX+ have 4Mb of memory, which is used for double-buffering and optimisation, and has a maximum supported resolution of 1600x1280. Note that unlike some PC graphics adaptors this memory CANNOT be used to give more than 8 bit colour.

The SparcStation LX has an on-board GX with a slot for a 1Mb VSIMM. This optional extra memory can be used to support higher display resolutions or for double-buffering.

For information on identifying the cgsix from software, look elsewhere or use fbinfo.

Double width GX: Rev 1
Double width GX: Rev 2
Single width GX: Rev 8
Single width GX
TGX - Older model. Chip sometimes printed with Sun logo and TURBO XGX.
TGX - Newer model. New names (mixed case).
TGX Plus. Older model. Same chip and names as TGX (501-2325)
TGX Plus. Newer model.
There is no functional difference between the older and newer versions of the TGX and TGXplus

cgtwelve

The cgtwelve is also known as the GS. This is a large card that takes up 3 SBus slots, and thus can only be used in machines that have 3 slots horizontally, such as SparcStations 1, 1+ and 2. It provides 8 or 24 bit graphics, but is fairly slow. It is not supported in 2.5 or later.

GT

The Graphics Tower is a 24 bit accelerated 3D graphics system. The tower itself is a seperate box, which is connected to the Sun through a single-width SBus interface card. As a console frame buffer it is unbearably slow. It is not supported in Solaris 2.5 and beyond, or in newer Sun machines.

cgfourteen

lso known as the SX and spam, this is a very different kind of frame buffer. Built in to the motherboard on the SS20, it is also available as an add-on card for SS10 and SS20 (only one add-on card is allowed). For each display a VSIMM is required; two types are available, 4Mb or 8Mb. The 8Mb VSIMM allows a resolution of 1280x1024 at a depth of 24 bits; the 4Mb VSIMM allows up to 1280x1024 at 8 bits or 1152x900 at 24 bits.
System memory can be reserved for use by the SX to improve performance using the command sxconfig.

It is not supported in SunOs 4.x, except as a console.

leo

Also known as the ZX or T(urbo)ZX, this is a 24 bit accelerated 3D graphics card. Both cards are double-width, but the TZX also requires extra cooling in the form of an additional double-width fan card, so effectively takes up 4 SBus slots.

tcx

These frame buffers attach to the AFX bus rather than the SBus, and are only supported in the SparcStation 4 and 5. The version for the Sparc 5 is also known as the S24 and is a 24 bit frame buffer. The version for the Sparc 4 is 8 bits only.

FFB family

The FFB was the first 24 bit frame buffer available for the Ultra machines. Several models exist; the FFB1 is available in single buffered (known as the Creator) and double buffered (known as the Creator 3D) formats; additionally the original Creator 3D is available in 66MHz and 75MHz forms. The FFB2/2+ is also available in single and double buffered configs, and also in two physical packages, depending on whether it is mounted horizontally (for SBus based systems) or vertically (for PCI based systems).

PGX family

The second generation Ultras 5 and 10 (code-named Darwin Plus) have a revised version of the PGX based on the ATI Rage Pro chipset. Known as the PGX24 it has 4Mb of SGRAM memory and supports both seperate and composite sync formats. When in seperate sync mode they drive the VESA standard resolutions from 640x480 to 1280x1024.

The card supports both 8 and 24 bit visuals, but due to the architecture of the chipset the card it cannot support both simultaneously. Thus any legacy applications that require an 8-bit color visual will be required to run in the 8-bit mode (disabling 24-bit visuals). Such applications need to be updated to take advantage of 24 bit visuals; users should contact the software vendor and request a patch.

AFB family

The AFB or Elite 3D series is the current high-end 3D graphics card. It supports all the features of the Creator 3D and adds such features as hardware-accelerated lighting.

Why are 24 bit Frame Buffers so expensive compared to a PC?

An often-heard complaint is "Why can't Sun sell a 24 bit frame buffer for $200 like I can get for my PC?". Regular viewers will remember that this section of the document had a detailed explanation of why this wasn't a fair comparison. However Sun's announcement of support for PCI bus architecture should change all that. It will now be possible for manufacturers to release Sun versions of their graphics products. Whether this boost to competition in the marketplace will result in a $200 24 bit frame buffer remains to be seen.

I'm confused by all these Creator boards. What's the story, Morning Glory?

You're not the only one. The difference between Creator and Creator 3D is the amount of on-board memory. Creator 3D has 15 MB of 3DRAM whereas Creator has only 5MB. This makes no difference to the raw geometry rendering speed, but double buffering and Z-buffering will be performed in software on the plain Creator, whereas Creator 3D will be hardware-assisted as it has the extra bit-planes to store this data.

The Series 2 has a 50% performance speedup and supports 1920x1200 in single buffer mode, YCC->BGR conversion and OpenGL depth cueing.

The Series 3 has programmable gamma correction, has multiple hardware colormaps and management software and has hardware stencil support.

Note that this table only shows the configurations that are supported - ie have been formally qualified after extensive testing. Other configurations may work, for example FFB2/2+ or AFB in an Ultra 1, but are not officially supported.