Sun SPARCStation 20
Introduced in 1989 Sun SPARCStation series of
computers was popular among smaller UNIX machines. They allowed to use
Unix-type operating system on a small computer with effective CPU and
larger amount of memory. The last model of this series was SPARCStation
20 released in 1994 or 95 (developed under codename "Kodiak"). It has a
nice expansion capabilities using horizontally mounted boards while
preserving a small "pizza-box" type casing. SPARCStation 20 can have
multiple CPUs to support large computations and maximum amount of RAM
was 512MB - unimaginable in mid-1990s. These computers were used in
applications where larger processing power was needed - in graphics,
rendering, or computer simulation. Later many expansions came in,
including 200MHz CPUs.
According to this article, quad-CPU SPARCStation 20s were used to render the famous Toy Story movie (another photo from Reddit).
|Year of unit||1995|
|Year of introduction||1994-5|
|Class||Sun SPARC (sun4m)|
|CPU||SuperSPARC 390Z56G (390Z55)|
|ROM||Sun boot ROM|
|Graphics||Sun TurboGX graphics card
(2D acceleration, 8-bit)
|System expansion bus||Sun MBus (for CPU)
Sun SBus (expansions)
|Floppy/removable media drives||1x 1.44MB? 3.5" FDD
1x SCSI CD-ROM drive
|Hard disk:||IBM 4.3GB, SCSI, SCA|
Peripherals in collection:
|Operating system(s):||Sun Solaris 2.6|
My unit has been used in some software development company. It ended in my hands from e-waste with BSD on its hard disk. I formatted it and put a fresh inastll of Solaris 2.6 with Common Desktop Environment as well as Sun StarOffice 5.1. Afte reworking RTC chip to support external battery it works.
The computer contains a chip, M48T18, which has embedded a Lithium non-rechargeable battery. The procedure to rework it to use normal CR2032 battery is described in Sun Ultra1 page.
If the unit still doesn't start, it should be checked
using serial port debugging. Prepare another PC with serial port and
terminal software, even HyperTerminal can do its job. Remove CPU board.
You will find two jumpers (not the one closer to PSU!) named J0801
and J0802, they are responsible for deciding is serial port RS485 or
RS232. Move the jumpers closer to power supply to switch serial ports to
Now connect the another PC. Look for "A/B" connector on the rear, connect its pin 7 to serial port's GND line and pin 2 to PCs "Rx". You are ready. Set PC's terminal to 9600baud, 8-bit, no parity, 1 stop bit and turn the Sun on.
The first thing you should see is the following:
This appears almost instantly on reset signal/power on. Then it will start tests like:
10/20 UP/MP POST version VRV3.45 (09/11/95)
CPU_#0 TI, TMS390Z55(5.x) 1Mb External cache
CPU_#1 ******* NOT installed *******
CPU_#2 ******* NOT installed *******
CPU_#3 ******* NOT installed *******
<<< CPU_00000000 on MBus Slot_00000000 >>> IS RUNNING (MID = 00000008)
MMU Context Table Reg Test
MMU Context Register Test
MMU TLB Bit Pattern Tests
MMU Flush Tests
. . .
and watch for results.
Continuing the previous section, if the battery is bad (and usually is) it will stuck for a while in "Setting Real Time Clock" and then:
Starting real time clock...
Incorrect configuration checksum;
Setting NVRAM parameters to default values.
Setting diag-switch? NVRAM parameter to true
It means that you have to replace or rework NVRAM and configure it like Sun Ultra1, but with System ID 72. As with this Sun, you can always call the boot prompt by holding Stop+A at boot (at white screen). Installing operating system doesn't look different than in Sun Ultra1 and you should be also careful not to damage your hard disk by erasing its own geometry tables.
There is a common misconception about place from which this computer can boot. Some sources inform that SPARCStation can't boo from partitions larger than 2GB. This is not true, it cannot boot from partitions which are placed past the first 2GB on a drive. So by carefully partitioning the disk when installing OS (and moving the swap somewhere else, as it goes as first or second by default) it is possible to have root partition bigger than 2GB.
It is possible to install Solaris 2.4 up to 9 (it is 2.4, 2.5, 2.6, 7, 8, 9, they dropped "2." with version 7) but for a good performance 2.5 or 2.6 is enough. It is theoretically possible to get Linux or BSD on it, but with their bloated X environments it will not go well as CPU and memory are limited.
A typical upgrade in this Sun is RAM. It can get maximum 64MB in one stick, so 128MB sticks will not work. Be careful where you put the RAM - check in a service manual for banks order as RAM must be in continuous banks. If not, the boot prompt will not detect any error, but the system will panic.
To upgrade CPU, not only a new CPU board is needed, but in many cases, especially non-Sun CPUs like Ross ones, it is also needed to replace the EPROM.
If the CD drive doesn't work, another CD drive or recorder may be freely used to boot and install OS. Hard disk is an ordinary SCA drive used e.g. in some servers. Remember only to make drive label and then partition, not low-level format it.
There are two methods of upgrading video performance: First is adding video memory in a common SIMM like typical Sun's memory expansions. The second one is installing a separate video board with own accelerator chip and memory.
https://docs.oracle.com/cd/E19127-01/sparc20.ws/801-6189-12/801-6189-12.pdf - Service manual
http://www.jax184.com/projects/sparc20/sparc20.html - A much upgraded version in a blog post
http://blogs.dailynews.com/click/2009/02/18/sparcstation-20-solaris-9-inst/ - Someone tried BSD on it
http://shrubbery.net/~heas/sun-feh-2_1/Systems/4m-System/4mSYSTEM_Sstation_20.html - Service guide with drawings
http://mbus.sunhelp.org/systems/sun/ss20.htm - Information about expansions
http://faqaboss.sunhelp.org/ - Faq about old Sun systems
http://www.sunhelp.org/faq/FrameBuffer.html - Sun Graphics boards FAQ
http://www.clock.org/~fair/computers/suns.html - Table of Sun systems