DDR4 SDRAM computer buses have migrated towards replacing parallel buses with serial buses, for example by the evolution of Serial ATA replacing Parallel ATA, PCI Express replacing PCI, and serial ports replacing parallel ports. In general, serial buses are easier to scale up and have fewer wires/traces, making circuit boards using them easier to design. In the longer term, experts speculate that non-volatile RAM types like PCM (phase-change memory), RRAM (resistive random-access memory), or MRAM (magnetoresistive random-access memory) could replace DDR4 SDRAM and its successors. GDDR5 SGRAM is a graphics type of DDR3 synchronous graphics RAM, which was introduced before DDR4, and
Sun-1 It was also the console port if no graphical display was installed in the system. Serial port B was wired as a Data Terminal Equipment (DTE) port and had no modem control. Both serial ports could also be used as terminal ports and quite often were allowing 3 people to use one workstation, although two did not have graphical displays. The 16-bit parallel port was a special purpose port for connecting 8-bit parallel port keyboard and 8-bit parallel port optical mouse for workstations with graphical displays. The parallel port was never used as a general purpose parallel printer port. The