The Sun386i (codenamed Roadrunner) was a hybrid UNIX workstation/PC compatible computer system produced by Sun Microsystems, launched in 1988. It was based on the Intel 80386 microprocessor but shared many features with the contemporary Sun-3 series systems.
Unlike the Sun-3 models, the Sun386i had a PC-like motherboard and "mini-tower"-style chassis. Two variants were produced, the Sun386i/150 and the Sun386i/250 with a 20 or 25 MHz CPU respectively. The motherboard included the CPU, 80387 FPU, 82380 timer/DMA/interrupt controller and a custom Ethernet IC called BABE ("Bus Adapter Between Ethernet"). Floppy disk, SCSI, RS-232 and Centronics parallel interfaces were also provided, as were four ISA slots (one 8-bit, three 16-bit) and four proprietary 32-bit "local" bus slots. The latter were used for RAM and frame buffer cards.
Two type of RAM card were available, a 4 or 8MB card, and the "XP Cache" card, incorporating up to 8MB with an 82385 cache controller and 32 kB of cache SRAM. Up to two memory cards could be installed, to give a maximum RAM capacity of 16MB.
Mass storage options were either 91 or 327 MB internal SCSI hard disks and a 1.4 MB 3.5 in floppy drive. A storage expansion box that holds two more disks could be mounted to the top of the chassis.
Frame buffer options included the 1024x768 or 1152x900-pixel monochrome BW2 card, the 8-bit color CG3 with similar resolutions, or the accelerated 8-bit color CG5, otherwise known as the Roadracer or GXi framebuffer. This used the TI TMS34010 graphics processor and had a resolution of 1152x900. In addition, one could install a "SunVGA" accelerator card in the ISA expansion slot that would allow a DOS session to display a full VGA window on the desktop.
The Sun386i's firmware was similar to the Sun-3's "PROM Monitor". A 386 port of SunOS was the native operating system of the 386i. SunOS releases 4.0, 4.0.1 and 4.0.2 supported the architecture. A beta version of SunOS 4.0.3 for the 386i also existed but was not generally available, except possibly to the U.S. government. Included with SunOS were the SunView GUI and VP/ix MS-DOS emulator. This ran as a SunOS process and thus allowed multiple MS-DOS session to be run simultaneously, a major selling point of the Sun386i. Unix long file names were accessed using a mapping to DOS 8.3 filenames, the file names being modified to include a tilde and to be unique as far as possible. This system is similar to, but predates, that used for long file names in Microsoft's VFAT. Special drive letters were used including H: for the user's home directory and D: for the current working directory when the DOS shell was started. The C: drive corresponded to a file in the Unix file system which appeared to DOS as a 20 MByte hard disk. This was used especially for the installation of copy-protected software; files in this virtual drive were inaccessible to Unix programs.
The Sun386i version of SunOS included many features not found in the versions then shipped with Sun-3 workstations (and later with then-new SPARC workstations), in addition to VP/ix. These additions focused on ease of use for end users who were likely not to be UNIX experts, and included enhanced desktop tools (which, for the first time at Sun, used color by default) and an "out of box experience" that was painless and administrator-free, targeted to bring a system onto the network ("box to mail") in fifteen minutes. It used the pioneering Dynamic RARP network protocol. At the time, and for a few years afterwards until DHCP later became standard, no other vendors' workstations (or PCs) were as easy to install on TCP/IP networks.
An upgraded model, the Sun486i (codename Apache) was designed, incorporating a 25 MHz 80486 CPU and improved SCSI interface. A small pre-production batch was built but the product was canceled in 1990, before its official launch.
Easter egg 
The inside surface of the right side cover has the Roadrunner logo and the developer's signatures molded in.
- Jackson, Peter (July 1988). "Intel SYP-302 vs Sun386i/250'". Personal Computer World 11 (7): 112–123.
See also 
- Sun Microsystems
- The Sun Hardware Reference, Part 1
- Sun Field Engineer Handbook, 20th edition
- PC Week review of the Sun386i
- Some informative postings to the Sun386i mailing list
- Sun 386i/250 pictures and description