Double Data Rate Synchronous Dynamic Random-Access Memory is a double data rate (DDR) synchronous dynamic random-access memory (SDRAM) class of memory integrated circuits used in computers. DDR SDRAM, also retroactively called DDR1 SDRAM, has been superseded by DDR2 SDRAM, DDR3 SDRAM, DDR4 SDRAM and DDR5 SDRAM. None of its successors are forward or backward compatible with DDR1 SDRAM, meaning DDR2, DDR3, DDR4 and DDR5 memory modules will not work on DDR1-equipped motherboards, and vice versa.
A RAM drive is a block of random-access memory that a computer's software is treating as if the memory were a disk drive. RAM drives provide high-performance temporary storage for demanding tasks and protect non-volatile storage devices from wearing down, since RAM is not prone to wear from writing, unlike non-volatile flash memory. They are in a sense the reverse of virtual memory: RAM drive uses a volatile fast memory as if it's a nonvolatile slow memory. Virtual memory is the opposite.
Dynamic random-access memory is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal–oxide–semiconductor (MOS) technology. While most DRAM memory cell designs use a capacitor and transistor, some only use two transistors. In the designs where a capacitor is used, the capacitor can either be charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. The electric charge on the capacitors gradually leaks away; without intervention the data on the capacitor would soon be lost. To prevent this, DRAM requires an external memory refresh circuit which periodically rewrites the data in the capacitors, restoring them to their original charge. This refresh process is the defining characteristic of dynamic random-access memory, in contrast to static random-access memory (SRAM) which does not require data to be refreshed. Unlike flash memory, DRAM is volatile memory, since it loses its data quickly when power is removed. However, DRAM does exhibit limited data remanence.
Synchronous dynamic random-access memory is any DRAM where the operation of its external pin interface is coordinated by an externally supplied clock signal.
A DIMM, or Dual In-Line Memory Module, is a popular type of memory module used in computers. It is a printed circuit board with one or both sides holding DRAM chips and pins. The vast majority of DIMMs are standardized through JEDEC standards, although there are proprietary DIMMs. DIMMs come in a variety of speeds and sizes, but generally are one of two lengths - PC which are 133.35 mm (5.25 in) and laptop (SO-DIMM) which are about half the size at 67.60 mm (2.66 in).
Rambus DRAM (RDRAM), and its successors Concurrent Rambus DRAM (CRDRAM) and Direct Rambus DRAM (DRDRAM), are types of synchronous dynamic random-access memory (SDRAM) developed by Rambus from the 1990s through to the early 2000s. The third-generation of Rambus DRAM, DRDRAM was replaced by XDR DRAM. Rambus DRAM was developed for high-bandwidth applications and was positioned by Rambus as replacement for various types of contemporary memories, such as SDRAM.
The Power Macintosh G3 is a series of personal computers designed, manufactured, and sold by Apple Computer from November 1997 to August 1999. It represented Apple's first step towards eliminating redundancy and complexity in the product line by replacing eight Power Macintosh models with three: Desktop and Mini Tower models for professional and home use, and an all-in-one model for education. The introduction of the Desktop and Mini Tower models coincided with Apple starting to sell build-to-order Macs directly from its web site in an online store, which was unusual for the time as Dell was the only major computer manufacturer doing this. Apple's move to build-to-order sales of the Power Macintosh G3 also coincided with the acquisition of Power Computing Corporation, which had been providing telephone sales of Macintosh clones for more than two years.
Double Data Rate 2 Synchronous Dynamic Random-Access Memory is a double data rate (DDR) synchronous dynamic random-access memory (SDRAM) interface. It is a JEDEC standard (JESD79-2); first published in September 2003. DDR2 succeeded the original DDR SDRAM specification, and was itself succeeded by DDR3 SDRAM in 2007. DDR2 DIMMs are neither forward compatible with DDR3 nor backward compatible with DDR.
CompactFlash (CF) is a flash memory mass storage device used mainly in portable electronic devices. The format was specified and the devices were first manufactured by SanDisk in 1994.
Registered memory is computer memory that has a register between the DRAM modules and the system's memory controller. A registered memory module places less electrical load on a memory controller compared to an unregistered one. Registered memory allows a computer system to remain stable with a higher number of memory modules than it would have otherwise.
Double Data Rate 3 Synchronous Dynamic Random-Access Memory is a type of synchronous dynamic random-access memory (SDRAM) with a high bandwidth interface, and has been in use since 2007. It is the higher-speed successor to DDR and DDR2 and predecessor to DDR4 synchronous dynamic random-access memory (SDRAM) chips. DDR3 SDRAM is neither forward nor backward compatible with any earlier type of random-access memory (RAM) because of different signaling voltages, timings, and other factors.
The Apple Network Server (ANS) was a line of PowerPC-based server computers designed, manufactured and sold by Apple Computer, Inc. from February 1996 to April 1997. It was codenamed "Shiner" and originally consisted of two models, the Network Server 500/132 and the Network Server 700/150, which got a companion model, the Network Server 700/200 with a faster CPU in November 1996.
The i-RAM was a PCI card-mounted, battery-backed RAM disk that behaved and was marketed as a solid-state storage device. It was produced by Gigabyte and released in June 2005, at a time when genuine solid-state storage solutions were generally still less affordable than an i-RAM product with superficially similar capabilities. The i-RAM utilized DRAM, a type of volatile memory, and was equipped with a lithium-ion battery to provide backup power. This backup power was necessary only when the host computer was either unplugged or completely powered down. Under normal conditions, the i-RAM could draw sufficient power from the PCI bus for RAM refresh, as the PCI bus maintains standby power even when an ATX system is shut down. However, the preservation of the DRAM's contents was limited to a duration of 10 to 16 hours, depending on the configuration, after the power supply was completely interrupted.
A solid-state drive (SSD) is a solid-state storage device. It provides persistent data storage using no moving parts. It is sometimes called semiconductor storage device or solid-state device; it is also called solid-state disk because it is frequently interfaced to a host system in the same manner as a hard disk drive.
The Open NAND Flash Interface Working Group is a consortium of technology companies working to develop open standards for NAND flash memory and devices that communicate with them. The formation of ONFI was announced at the Intel Developer Forum in March 2006.
Double Data Rate 4 Synchronous Dynamic Random-Access Memory is a type of synchronous dynamic random-access memory with a high bandwidth interface.
The Digital Personal Workstation, code named "sports car", is a family of entry-level to mid-range workstation computers developed and manufactured by Digital Equipment Corporation (DEC). These workstations are based on the DEC Alpha and Intel Pentium Pro or Pentium II microprocessors. Members of this family can run the Digital UNIX, OpenVMS, and Windows NT operating systems. The i-Series, based on Pentium Pro, was introduced first, on September 23, 1996.
The A Series desktops are part of Lenovo’s ThinkCentre product line. Formerly an IBM brand, Lenovo acquired the ThinkCentre desktop brand following its purchase of IBM’s Personal Computing Division (PCD) in 2005. The first desktop in the A Series was the ThinkCentre A50p. Lenovo has released A Series desktops in multiple form factors, ranging from traditional tower, to small form factor, and all-in-ones (AIOs).
HyperCloud Memory (HCDIMM) is a DDR3 SDRAM dual in-line memory module (DIMM) used in server applications requiring a great deal of memory. It was initially launched in 2009 at the International Supercomputing Conference by Irvine, California, based company, Netlist Inc. It was never a JEDEC standard, and the main server vendors supporting it were IBM and Hewlett Packard Enterprise.
Double Data Rate 5 Synchronous Dynamic Random-Access Memory is a type of synchronous dynamic random-access memory. Compared to its predecessor DDR4 SDRAM, DDR5 was planned to reduce power consumption, while doubling bandwidth. The standard, originally targeted for 2018, was released on July 14, 2020.
