Storage

Storage is the major issue with each and every system. In embedded industry the storage devices are selected according to the task and requirement specifications. Various storage devices are discussed here, which can be used according to the situations. These include disk drives, compact flash, disk on chip, and disk on module. Disk drives are suitable in voluminous systems such as workstations. In extremely integrated circuits where the hard disks cannot fit, Flash memories solve the problem. Disk on chip and Disk on modules can be the solutions. But Disk on chip is quite expensive than general hard disk drives. Similarly in laptops and notebook computers compact flash is used to add more space.

Computer and Embedded Systems Memory

Memory is also an integrated circuit and refers to as memory chip. Memory chip contains the memory cells that store the data electronically. In computer's perspective memory is usually refers to RAM (random access memory) chips. Without RAM computers cannot read any program or perform any operations. Two common choices for computer memory include dynamic random access memory (DRAM) and static random access memory (SRAM).

Dynamic Random Access Memory (DRAM)

In DRAM chip the memory cell consists of only one transistor. Transistor decides that whether it is ‘1' or ‘0'. This depends upon the capacitors associated with the transistor. Data (1 or 0) stored in the capacitors must be refreshed.

Static Random Access Memory (SRAM)

SRAM chips contain memory cells consisting of six transistors. So SRAM cells do not require refreshes or updates to hold the data. SRAM is faster than DRAM because its read operation is non-destructive.

In DRAM extra time is required to restore contents of accessed memory addresses. Moreover static RAMs are expensive than dynamic RAMs due to the greater number of transistors.

Specialty Memory Chips for Processing

Besides computers embedded systems also require memories. For his purpose specialty memory chips are used. Specialty memory chips are the proprietary devices or products. Specialty memory chips can be the integral part of PDAs (personal digital assistants), smart phones, and other computing devices to increase processing. In such perspective RAM, DRAM, and FRAM chips are common.

Specialty Memory Chips for Storage

Specialty memory chips are also available to add more storage to the embedded systems or other electronic devices. Such memory chips include memory sticks and FLASH memories. Memory sticks are suitable for recording or carrying digital data such as audio, video, or photos. FLASH memory chips are used in digital cameras, USB (universal serial bus) drives, MP3 Players, and mobile phones.

Memory Chip Specifications

Size, form factor, transfer speed, power supply requirements, cooling, and quality of manufacture are important specifications of a memory chip. Specialty memory chips used in motion video and high quality audio usually require greater transfer speed.

Memory size depends upon the application requirements. Different memory chips operate at different power supplies. FRAM (ferroelectric random access memory) collect data for years without wearing out. Also FRAM operates at relatively low power. Manufacture quality includes demanding use, general use, or economy considerations,

Memory Chips and Operating System Requirements

Another important specification of a memory chip is its operating system compatibility. Memory chips contain operating system requirements. For example a RAM chip is compatible with PC100 front side bus. Similarly an embedded system memory chip specifies operating system requirements according to the model number or other specifications. For example memory chips compatible with a particular model of printer.