Path: utzoo!news-server.csri.toronto.edu!rutgers!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: RAM Information Message-ID: <19746@cbmvax.commodore.com> Date: 11 Mar 91 19:30:06 GMT References: Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 39 In article lcs@remus.rutgers.edu (Lyle C. Seplowitz) writes: >What is the difference between Dynamic RAM and Static RAM? Dynamic RAM is generally pretty dense memory. Each memory cell is composed of a single transistor and capacitor. Because charge gradually bleeds from the capacitor, Dynamic RAMs must be peridically "refreshed". Typically, addressing a DRAM is a two-step process. To increase density, the memory device uses a multiplexed address. First, a memory controller sends 1/2 the address, termed the "row" address. With that safely latched in place, the memory controller sends the "column" address, and the memory can then address that single location. Static RAM is generally pretty fast memory. Each memory cell is composed of several transistors, essentially one flip-flip per cell. This makes an SRAM much larger than a DRAM, but eliminates any need for refresh and any sense in a multiplexed addressing scheme. So the memory controller sends out a single address, and the SRAM responds by fetching or storing that addressed location. There's alot more to it than that, but typically, DRAM systems are slower and more complex than SRAM systems. They're also much larger per unit cost. >CSA's Mega-Midget Racer uses both DRAM and SRAM, why is the SRAM >faster than DRAM? Because it should be. >I assume that the DRAM is faster than standard faster RAM. That sentence doesn't make any sense. There is no such thing as "standard faster RAM". In most microcomputer systems today, some kind DRAM is used. SRAM is typically only used for cache memories or other small, time critical needs. >Lyle -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett