Sun-4 is a series of Unix workstations and servers produced by Sun Microsystems, launched in 1987. The original Sun-4 series were VMEbus-based systems similar to the earlier Sun-3 series, but employing microprocessors based on Sun's own SPARC V7RISC architecture in place of the 68k family processors of previous Sun models.
Models
Models are listed in approximately chronological order. In 1989, Sun dropped the "Sun-4" name for marketing purposes in favor of the SPARCstation and SPARCserver brands for new models, although early SPARCstation/server models were also assigned Sun-4-series model numbers. For example, the SPARCstation 1 was also known as the Sun 4/60. This practice was phased out with the introduction of the SPARCserver 600MP series in 1991. The term Sun-4 continued to be used in an engineering context to identify the basic hardware architecture of all SPARC-based Sun systems. Sun 4/110, 4/150, 4/260 and 4/280 systems upgraded with the Sun 4300 CPU board were referred to as the 4/310, 4/350, 4/360 and 4/380 respectively.
Sun-4 architecture
The Sun-4 architecture refers to the VME-based architecture described above and used in the Sun 4/100, 4/200, SPARCserver 300 and SPARCserver 400 ranges. Sun-4 support was included in SunOS 3.2 onwards and Solaris 2.1 to 2.4. OpenBSD and NetBSD also will run on the Sun-4 architecture families. Several variations on the Sun-4 architecture were subsequently developed and used in later computer systems produced by Sun and other vendors. These comprised: ;Sun-4c: This desktop workstation/low-end server variant substituted the 32-bit SBusexpansion bus in place of VME and introduced a new MMU design. Supported by SunOS 4.0.3c onwards and Solaris 2.0 to 7. ;Sun-4e: A hybrid Sun-4c/VME architecture found in the SPARCengine 1 VME embedded controller. This board was originally designed by Force Computers and licensed to Sun. Supported by SunOS 4.0.3e and 4.1e and Solaris 2.1 to 2.4. ;Sun-4m: Originally a multiprocessor Sun-4 variant, based on the MBus processor module bus introduced in the SPARCserver 600MP series. The Sun-4m architecture later also encompassed non-MBus uniprocessor systems such as the SPARCstation 5, utilizing SPARC V8-architecture processors. Supported by SunOS 4.1.2 onwards and Solaris 2.1 to 9. SPARCserver 600MP support was dropped after Solaris 2.5.1. ;Sun-4d: A high-end multiprocessor architecture, based on the XDBus processor interconnect, scalable up to 20 processors. The only Sun-4d systems produced by Sun were the SPARCserver 1000 and SPARCcenter 2000 series. The Cray CS6400 was also nominally a Sun-4d machine, although it required a custom version of Solaris. Supported by Solaris 2.2 to 8. ;Sun-4u: - this variant introduced the 64-bitSPARC V9processor architecture and UPA processor interconnect first used in the Sun Ultra series. Supported by 32-bit versions of Solaris from the version 2.5. The first 64-bit Solaris release for Sun4u is Solaris 7. UltraSPARC I support was dropped after Solaris 9. Solaris 10 supports Sun4u implementations from UltraSPARC II to UltraSPARC IV. ;Sun-4u1: Sometimes used to identify the Sun Enterprise 10000 64-way multiprocessor server architecture. The Starfire is supported by Solaris 2.5.1 onwards. ;Sun-4us: A variant of Sun-4u specific to Fujitsu PRIMEPOWER systems based on SPARC64 V processors. ;Sun-4v: A variation on Sun-4u which includes hypervisor processor virtualization; introduced in the UltraSPARC T1multicore processor. Supported by Solaris version 10 starting from release 3/05 HW2, and Solaris 11.
