DECsystem was a line of server computers from Digital Equipment Corporation.
They were based on MIPS architecture processors and ran DEC's version of the UNIX operating system, called ULTRIX.
They ranged in size from workstation-style desktop enclosures to large pedestal cabinets.
Once the console transferred control of the computer to the MIPS processor the MicroVAX sat essentially unused until the next boot.
The DECsystem 5500 shipped in a BA430 enclosure, which provided a 12-slot backplane and room for four mass storage devices.
The series comprised the DECsystem 5810, 5820, 5830, and 5840, with the third digit referring to the number of processors.
These systems were the MIPS/RISC alternatives of the VAX 6000 operating the XMI and BI bus.
[2] The 5810 and 5820, using 25 MHz R3000 microprocessors and R3010 floating-point coprocessors, were introduced on 11 July 1989.
Their intended replacement was the DEC 3000 Model 800S AXP packaged in a similar rack-mountable enclosure.
The CPU module contained an integrated TURBOchannel Extender, the power supply and a blower, which cooled the system.