Types of Ram

5 Types Of RAM


SDRAM
Definition- SDRAM (synchronous DRAM) is a generic name for various kinds of dynamic random access memory (DRAM) that are synchronized with the clock speed that the microprocessor is optimized for. This tends to increase the number of instructions that the processor can perform in a given time. The speed of SDRAM is rated in MHz rather than in nanoseconds (ns). This makes it easier to compare the bus speed and the RAM chip speed. You can convert the RAM clock speed to nanoseconds by dividing the chip speed into 1 billion ns (which is one second). For example, an 83 MHz RAM would be equivalent to 12 ns.The replacement for DRAM, FPM, and EDO, SDRAM synchronizes memory access with the CPU clock for faster data transfer. Basically, one block of data can be sent to the CPU while another is being prepared for access.

DDR (Double Data Rate SDRAM)
Definition-DDR basically doubles the rate of data transfer of standard SDRAM by transferring data on the up and down tick of a clock cycle. DDR memory operating at 333MHz actually operates at 166MHz * 2 (aka PC333 / PC2700) or 133MHz*2 (PC266 / PC2100). DDR is a 2.5 volt technology that uses 184 pins in its DIMMs. It is incompatible with SDRAM physically, but uses a similar parallel bus, making it easier to implement than RDRAM, which is a different technology.


Rambus DRAM (RDRAM)
Definition-Despite it's higher price, Intel has given RDRAM it's blessing for the consumer market, and it will be the sole choice of memory for Intel's Pentium 4. RDRAM is a serial memory technology that arrived in three flavors, PC600, PC700, and PC800. PC800 RDRAM has double the maximum throughput of old PC100 SDRAM, but a higher latency. RDRAM designs with multiple channels, such as those in Pentium 4 motherboards, are currently at the top of the heap in memory throughput, especially when paired with PC1066 RDRAM memory.


EDO DRAM
Definition-EDO DRAM gave people up to 5% system performance increase over DRAM. EDO DRAM is like FPM DRAM with some cache built into the chip. Like FPM DRAM, EDO DRAM maxes out at about 50 MHz. Early on, some system makers claimed that if you used EDO DRAM you didn't need L2 cache in your computer to get decent performance. They were wrong. It turns out that EDO DRAM works along with L2 cache to make things even faster, but if you lose the L2 cache, you lose a lot of speed.

SIMM (single in-line memory module)

Definition:A memory-chip module with 72 or 30 pins that connect the module to the PC motherboard. SIMMs are normally found in older systems. They support 32-bit and 16-bit data transfers, respectively.

APPLICATION SOFTWARE

CUSTOM SOFTWARE

DEFINITION: Custom software (also known as Bespoke software) is a type of software that is developed either for a specific organization or function that differs from or is opposite of other already available software (also called off-the-shelf or COTSsoftware). It is generally not targeted to the mass market, but usually created for companies, business entities, and organizations. Custom software is also when companies or governments pay for customized software for budget or project managing.

Examples of bespoke software include commercial products such as commercial websites, business databases and software for governments. Non-commercial custom software development is common in academic and open source circles.

Complex custom software can be developed on an increasingly small scale through the rise of rapid application development frameworks. This means that smaller companies, charities or even individuals are able to benefit from complex software based on pre-built building blocks which are then customised to suit.


PACKAGE SOFTWARE
DEFINITION: software package: A package that consists of (a) one or more computer programs and possibly related material such as utility programs or tutorial programs, recorded on a medium suitable for delivery to the user, and from which the user can transfer the program(s) to a data-processing device, and (b) instructional materials such as handbooks and manuals, update information, and possibly support services information. Note 1: The computer programs may consist, for example, of application programs or operating systems, and are usually written in a high-level or low-level language, respectively. Note 2: The recording medium is usually a magnetic diskette or an optical compact disk.


SHAWARE

DEFINITION: Shareware distribution gives users a chance to try software before buying it. If you try a Shareware program and continue using it after a reasonable evaluation period, you are expected to register. Individual programs differ on details -- some request registration while others require it, some specify a maximum trial period. With registration, you get anything from the simple right to continue using the software to an updated program with printed manual.
Shareware is a distribution method, not a type of software. You should find software that suits your needs and pocketbook, whether it is commercial or Shareware. The Shareware system makes fitting your needs easier, because you can try before you buy. And because the overhead is low, prices are low also. Shareware has the ultimate money-back guarantee -- if you don't use the product, you don't pay for it.



FREEWARE

DEFINITION: Like shareware, freeware is software you can download, pass around, and distribute without any initial payment. However, the great part about freeware is that you never have to pay for it. No 30 day limit, no demo versions, no disabled features -- it's totally free. Things like minor program updates and small games are commonly distributed as freeware. Though freeware does not cost anything, it is still copyrighted, so other people can't market the software as their own.


PUBLIC DOMAIN SOFTWARE

DEFINITION: Programs that are uncopyrighted because their authors intended to share them with everyone else are in the public domain. The UNIX community has developed a number of such programs over the years. Programs in the public domain can be used without restriction as components of other programs. When reusing such code, it is good to understand its history so that you can be sure it really is in the public

What are the different between ASCII CODE And UNICODE?

ASCII is a seven-bit encoding technique which assigns a number to each of the 128 characters used most frequently in American English. This allows most computers to record and display basic text. ASCII does not include symbols frequently used in other countries, such as the British pound symbol or the German umlaut. ASCII is understood by almost all email and communications software.

Unicode is an attempt by ISO and the Unicode Consortium to develop a coding system for electronic text that includes every written alphabet in existence. Unicode uses 8-, 16-, or 32-bit characters depending on the specific representation, so Unicode documents often require up to twice as much disk space as ASCII or Latin-1 documents. The first 256 characters of Unicode are identical to Latin-1. Not all email or communications software can understand the Unicode character set.

ASCII CODE

Acronym for the American Standard Code for Information Interchange. Pronounced ask-ee, ASCII is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127. For example, the ASCII code for uppercase M is 77. Most computers use ASCII codes to represent text, which makes it possible to transfer data from one computer to another.

Text files stored in ASCII format are sometimes called ASCII files. Text editors and word processors are usually capable of storing data in ASCII format, although ASCII format is not always the default storage format. Most data files, particularly if they contain numeric data, are not stored in ASCII format. Executable programs are never stored in ASCII format.

The DOS operating system uses a superset of ASCII called extended ASCII or high ASCII. A more universal standard is the ISO Latin 1 set of characters, which is used by many operating systems, as well as Web browsers.