Write a short note on read only memory function

Inside the plastic casing is a small printed circuit board, which has some power circuitry and a small number of surface-mounted integrated circuits ICs. Drives typically use the USB mass storage device class to communicate with the host. These had limited capacity, were slow for both reading and writing, required complex high-voltage drive circuitry, and could be re-written only after erasing the entire contents of the chip.

Write a short note on read only memory function

Using robot software to mass-download the site degrades the server and is prohibited.

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See here for more. Find The PC Guide helpful? View over of my fine art photos any time for free at DesktopScenes. ROM is a type of memory that normally can only be read, as opposed to RAM which can be both read and written.

There are two main reasons that read-only memory is used for certain functions within the PC: The values stored in ROM are always there, whether the power is on or not.

A ROM can be removed from the PC, stored for an indefinite period of time, and then replaced, and the data it contains will still be there. For this reason, it is called non-volatile storage. A hard disk is also non-volatile, for the same reason, but regular RAM is not.

The fact that ROM cannot easily be modified provides a measure of security against accidental or malicious changes to its contents. You are not going to find viruses infecting true ROMs, for example; it's just not possible.

Read-only memory is most commonly used to store system-level programs that we want to have available to the PC at all times. Having this in a permanent ROM means it is available when the power is turned on so that the PC can use it to boot up the system. Remember that when you first turn on the PC the system memory is empty, so there has to be something for the PC to use when it starts up.

While the whole point of a ROM is supposed to be that the contents cannot be changed, there are times when being able to change the contents of a ROM can be very useful. There are several ROM variants that can be changed under certain circumstances; these can be thought of as "mostly read-only memory".

A regular ROM is constructed from hard-wired logic, encoded in the silicon itself, much the way that a processor is. It is designed to perform a specific function and cannot be changed.

This is inflexible and so regular ROMs are only used generally for programs that are static not changing often and mass-produced. This is a type of ROM that can be programmed using special equipment; it can be written to, but only once.

This is useful for companies that make their own ROMs from software they write, because when they change their code they can create new PROMs without requiring expensive equipment. This is similar to the way a CD-ROM recorder works by letting you "burn" programs onto blanks once and then letting you read from them many times.

A little glass window is installed in the top of the ROM package, through which you can actually see the chip that holds the memory. Ultraviolet light of a specific frequency can be shined through this window for a specified period of time, which will erase the EPROM and allow it to be reprogrammed again.

Obviously this is much more useful than a regular PROM, but it does require the erasing light.

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Here we are blurring the line a bit between what "read-only" really means, but remember that this rewriting is done maybe once a year or so, compared to real read-write memory RAM where rewriting is done often many times per second!

This is not true; any location can be read from ROM in any order, so it is random access as well, just not writeable. RAM gets its name because earlier read-write memories were sequential, and did not allow random access.Read and write to a memory location.

Ask Question. up vote 4 down vote favorite. 2. and the hosting environment doesn't want you willy-nilly writing to another application's memory. You should only ever write to memory that you KNOW your program has access to, or you will have inexplicable crashes at runtime.

(note the spelling), which. ROM- (Read-only memory) Read-only memory (ROM) is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to need.

– refers to memory with both Read and Write capabilities •ROM: Read Only Memory – no capabilities for “online” memory Write operations – note WL routed in poly • will create a large RC delay for large SRAM array. ECE , Prof.

write a short note on read only memory function

A. Mason Lecture Notes Aug 18,  · Page 1 of 8 - ReadMemory function - posted in Scripts and Functions: Its not my first time using ReadProcessMemory functions to read 4byte value in a game client at certain memory address, but i always have difficulties copy and paste this and that declaring the functions so today, i made up my mind and wrap it up together into a library functionHere: .

Short for programmable read-only memory, a memory chip on which data can be written only once. Once a program has been written onto a PROM, it remains there forever.

Unlike RAM, PROMs retain their contents when the computer is turned off. A USB flash drive, also known as a thumb drive, pen drive, the speed in which the USB controller device can read and write data onto the flash memory, and the speed of the hardware bus, especially in the case of add-on USB ports.

Some preloaded drives are read-only, while others are configured with both read-only and user-writable.

c - Read and write to a memory location - Stack Overflow