PC Memory Architecture

PC Memory Architecture

CCNT50 (Basic Troubleshooting andMaintenance)

ContentsPhysical Memory

RAMROM

Memory ConsiderationsCAS Latency

Memory PackagingSIMM’sDIMM’sEarly Disk Drives

Hard Disk Drive BasicsFormatFile Systems

RAIDRemovable Media DrivesMagnetic StorageOptical StorageSolid-State Storage

Computer Architecture

In computer science and computer engineering, computer architecture or digital computer organization is the

conceptual design and fundamental operational structure of a computer system. It is a blueprint and functional

description of requirements and design implementations for the various parts of a computer, focusing largely on the way

by which the central processing unit (CPU) performs internally and accesses addresses in memory.

Physical Memory

RAM (Random Access Memory) – Primary memory

in the computer. It is a volatile type of memory where the information is lost after the

power is switched off.

Physical MemoryTwo Types of RAM

DRAM (Dynamic Random Access Memory) - is a type of random access memory that

stores each bit of data in a separate capacitor within an integrated circuit. It is called

dynamic because it loses all data when power is removed.

The main memory (the "RAM") in personal computers is Dynamic RAM (DRAM), as is the "RAM" of home game consoles (PlayStation, Xbox 360 and Wii), laptop, notebook and workstation computers.

Physical MemorySRAM (Static Random Access Memory) - is a type of semiconductor memory where the word static indicates that, unlike dynamic RAM (DRAM), it does not need to be periodically refreshed. But it is still volatile in the conventional sense that data is eventually lost when the memory is not powered.

Memory Considerations

Column Address Strobe (CAS) latency, or CL, is the delay time between the

moment a memory controller tells the memory module to access a particular

memory column on a RAM memory module, and the moment the data from given array location is available on the module's output pins. In general, the

lower the CAS latency, the better.

Memory Packaging

The packaging is simply the entire makeup of a unit of

memory.

Memory Packaging

SIMM’s and DIMM’sA SIMM, or single in-line memory module, is a type of memory

module containing random access memory used in computers from the early 1980s to the late 1990s. It differs from a dual in-line

memory module (DIMM), the most predominant form of memory module today, in that the contacts on a SIMM are redundant on

both sides of the module.

Memory PackagingEarly Disk Drives (from 1980 up to present)

1980 - The world's first gigabyte-capacity disk drive, the IBM 3380, was the size of a refrigerator, weighed 550 pounds (about 250 kg), and had a price tag of $40,000

Early Disk Drives (from 1980 up to present)

1986 - Standardization of SCSI

1989 - Jimmy Zhu and H. Neal Bertram from UCSD proposed exchange decoupled granular microstructure for thin film disk storage media, still used today.

1991 - 2.5-inch 100 megabyte hard drive


1991 - PRML Technology (Digital Read Channel with 'Partial Response Maximum Likelihood' algorithm)

1992 - first 1.3-inch hard disk drive - HP Kittyhawk


1994 - IBM introduces Laser Textured Landing Zones (LZT)1996 - IBM introduces GMR (Giant MR) Technology for read sensors1998 - UltraDMA/33 and ATAPI standardized


1999 - IBM releases the Microdrive in 170 MB and 340 MB capacities2002 - 137 GB addressing space barrier broken


1999 - IBM releases the Microdrive in 170 MB and 340 MB capacities2002 - 137 GB addressing space barrier broken


2003 - Serial ATA introduced2005 - First 500 GB hard drive shipping (Hitachi GST)


2005 - Serial ATA 3Gbps standardized2005 - Seagate introduces Tunnel MagnetoResistive Read Sensor (TMR) and Thermal Spacing Control2005 - Introduction of faster SAS (Serial Attached SCSI)2005 - First Perpendicular recording HDD shipped: Toshiba 1.8-inch 40/80 GB[7]


2006 - First 750 GB hard drive (Seagate)2006 - First 200 GB 2.5" hard drive utilizing

Perpendicular recording (Toshiba)2006 - Fujitsu develops heat-assisted

magnetic recording (HAMR) that could one day achieve one terabit per square inch

densities.[8]



2007 - First 1 terabyte hard drive[9] (Hitachi GST)


2008 - First 1.5 terabyte hard drive[10] (Seagate)


2009 - First 2.0 terabyte hard drive[11] (Western Digital)


2009 - First 2.0 terabyte hard drive[11] (Western Digital)

2010 - First 3TB Hard drive (Seagate)


Hard Disk Drive Basics

Hard Disk Drives - is a non-volatile storage device for digital data. Data is encoded magnetically by read/write heads that float on a cushion of air above the platters.

Hard Disk Drive Basics

FORMAT and FILE SYSTEM - A disk file system is a file system designed for the storage of files on a data storage device

RAIDRAID, an acronym for redundant array of independent disks or redundant array of inexpensive disks, is a technology that provides increased storage reliability through redundancy, combining multiple low-cost, less-reliable disk drives components into a logical unit where all drives in the array are interdependent. RAID combines two or more physical hard disks into a single logical unit using special hardware or software. Hardware solutions are often designed to present themselves to the attached system as a single hard disk, so that the operating system would be unaware of the technical workings.

Removable Media Drives

In computer storage, removable media refers to storage media which is designed to be removed from the computer without powering the computer off.Some types of removable media are designed to be read by removable readers and drives.


Magnetic storage and magnetic recording are terms from engineering referring to the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetization in a magnetizable material to store data and is a form of non-volatile memory.



Optical storage is a term from engineering referring to the storage of data on an optically readable medium. Data is recorded by making marks in a pattern that can be read back with the aid of light. A common modern technique used by computers involves a tiny beam of laser light precisely focused on a spinning disc.


A solid-state drive (SSD) is a data storage device that uses solid-state memory to store persistent data. SSDs are distinguished from traditional hard disk drives (HDDs), which are electromechanical devices containing spinning disks and movable read/write heads. SSDs, in contrast, use microchips, and contain no moving parts.


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PC Memory Architecture