Computer Memory

A computer is an electronic device that takes raw data as input and, processes it, then provides the desired result. It has the potential to execute programmed computations quickly and with great accuracy. Put in another way, the computer receives input such as data and stores it together with instructions in memory (use them when required). The data is then processed and converted into valuable information. After that, it provides the result according to the inputs. Here, input means the unprocessed data that we want the machine to handle and then give us a response, and output refers to the outcome of the machine's processing of the unprocessed data, which may include data analysis, searching, distributing, storing, and more. Consequently, a computer is also referred to as a data processing system.

What is Memory?

The computer memory holds the data and instructions needed to process raw data and produce output. It is the same as a human mind, where data, information, and instructions are stored. It is a data storage device or a data storage component where instructions for processing data are kept along with the data that has to be processed. Both the input and the output can be held here.

The computer memory is divided into large number of small parts known as cells. Each cell has a unique address which varies from 0 to memory size minus one. Computer memory is of two types: Volatile (RAM) and Non-volatile (ROM). The secondary memory (hard disk) is referred as storage not memory.

Characteristics of Main Memory:

• It serves as the computer's main memory.
• As compared to secondary memory, it is faster computer memory.
• Typically, it is a volatile memory.
• Without primary memory, a computer system cannot run.
• These memories are semiconductors.

But, if we categorize memory on behalf of space or location, it is of four types:

• Register memory
• Cache memory
• Primary memory
• Secondary memory

How does computer memory work?

A program is loaded from secondary memory to primary memory when it is opened. There are several types of memory and storage, for example, a program being moved from a solid-state drive (SSD) to RAM (Random Access Memory). The opened software will be able to communicate with the computer's processor at a faster rate because primary storage is accessed more quickly. The main or primary memory can be accessed quickly from storage locations such as temporary memory slots.

Data in memory is only saved temporarily since memory is volatile. Data saved in volatile memory will be erased immediately whenever a computer is turned off. A file is transported to secondary memory for permanently storage when it is saved.

There are numerous kinds of memory present in a computer. Depending on the primary memory utilized, it will perform differently, but semiconductor-based memory is typically connected with memory. Integrated circuits utilizing metal-oxide-semiconductor (MOS) transistors based on silicon will be used to make semiconductor memory.

Types of computer memory

In general, memory can be classified into primary and secondary memory, however even when just talking about primary memory, there are many different types of memory. There are some examples of primary memory, such as follows:

• Cache memory: The cache, also known as a temporary storage area, is more readily available to the processor as compared to the main memory source of the computer system. It is mounted on a different chip that connects to the CPU via a bus or is frequently built directly into the CPU chip; hence, it is also known as CPU memory.
• RAM: The term refers to the fact that the processor can directly access any storage location. Random Access Memory, or RAM, is a piece of hardware that serves as the internal memory of the CPU. It is often found on a on the motherboard of a computer. When the computer is turned on, it enables the CPU to store programs, information, and result of the program. Also, it is a computer's read-write memory, which means data can be added to it as well as read from it.
• Dynamic RAM: A type of random-access memory that is used in computing systems (primarily PCs) is called dynamic random-access memory (DRAM). The data or program code required for a computer processor to operate is often stored in DRAM, which is a kind of semiconductor memory. Each piece of data is stored in DRAM in its own passive electrical component, which is located inside an integrated circuit board. Each electrical component has two value states, known as 0 and 1, in one bit.
• Static RAM: As long as SRAM receives power, it keeps data bits in its memory. It does not need to be refreshed on a regular basis, in contrast to DRAM, which stores bits in cells made up of a capacitor and a transistor.
• Double Data Rate SDRAM: Theoretically, DDR SRAM can increase the memory clock speed to at least 200 MHz. It is an SDRAM.
• Double Data Rate 4 Synchronous Dynamic RAM: DDR4 RAM is the successor to its preceding DDR2 and DDR3 iterations. It is a kind of DRAM that contains a high-bandwidth interface. Higher module density and lower voltage requirements are both possible with DDR4 RAM. It enables dual in-line memory modules (DIMMS) up to 64 GB; Also, higher data rate transfer speeds are paired with it.
• Rambus Dynamic RAM: A memory component called DRDRAM made a guarantee to transport up to 1.6 billion bytes per second. The RAM controller subsystem consists of RAM, a bus connecting RAM to the microprocessor, and computer-using devices that make up the subsystem.
• Read-only memory: ROM is often only read from and not written to, which is a type of computer storage. It is nonvolatile in nature, which means it stores data permanently. The programming code is stored in the ROM that enables a computer system to boot up or regenerate every time when it is turned on.
• Programmable ROM: PROM is ROM that a user can modify only once. Using a unique device known as a PROM programmer enables a user to customize a microcode program.
• Erasable PROM: EPROM is a type of computer memory that can be erased and re-used. It is programmable read-only memory PROM.
• Electrically erasable PROM: A user-modifiable ROM called an EEPROM can be repeatedly wiped and reprogrammed with the help of an using electrical voltage that is higher than usual. Unlike EPROM chips, EEPROMs can be changed without being taken out of the computer. However, an EEPROM chip must be completely deleted and reprogrammed, not just some parts of it.
• Virtual memory: A memory management method that enables the use of secondary memory just like it was a component of main memory. In order to compensate for physical memory shortages, virtual memory uses hardware and software to temporarily shift data from RAM to disk storage.

Memory vs. Storage

Although the terms "memory" and "storage" are frequently used interchangeably, there are some distinct and important differences between both. Simply said, storage is secondary memory, while memory is primary or main memory. Storage refers to where long-term data is stored, whereas memory refers to where short-term data is stored.

On a computer, the term "memory" is most frequently used to describe the main storage, such as RAM. Information is also processed in memory. With the help of RAM, users have the potential to access data that is stored for a short time. As primary memory is volatile, meaning it is not retained when the computer is shut off, the data is only stored for a brief period of time.

Data in a computer is stored in secondary memory, which is referred to as storage. A hard drive (HDD), often known as a hard disk drive, is an example of storage. Because storage is nonvolatile, data is not lost even after the computer is powered off and back on. For quick information retrieval, a running program may be in the main memory of the computer, but when the program is closed, it moves to secondary memory or storage.

The amount of storage and memory space that is accessible differs as well. As compared to memory, a computer will often have greater storage capacity. For instance, a laptop may have 250 GB of storage space and 8 GB of RAM. The reason for the difference in space is that a computer will not need to quickly access all the data stored on it at once; therefore, assigning about 8 GB of space will be plenty to run programs.

Due to the inconsistent usage of this terminology in modern technology, memory and storage can be difficult to understand. For instance, flash memory is a sort of secondary storage, whereas RAM can be referred to as primary storage. It may be simpler to talk about memory in terms of whether it is volatile or nonvolatile and storage in terms of whether it is primary or secondary in order to avoid misunderstanding.

Timeline of the history and evolution of computer memory

Memory was first limited to a few bytes of space in the early 1940s. The development of acoustic delay line memory was one of the more important indications of advancement at this period. Quartz crystals could be used as transducers to read and write bits, and delay lines could store bits in mercury as sound waves.

A few hundred thousand bits can be stored with the help of using this approach. Nonvolatile memory was first studied in the late 1940s, and magnetic-core memory, which allowed for memory recall in the absence of power, was developed. This technology had advanced and become widely used by the 1950s, which helped to bring about the creation of the PROM in 1956. Due to its extensive use, magnetic-core memory predominated as the primary memory technology until the 1960s.

In 1959, MOS semiconductor memory, also referred to as metal-oxide-semiconductor field-effect transistors, was developed. As a result, MOS transistors can be used as components for memory cell storage. In comparison to magnetic-core memory, MOS memory was less expensive and required less power. Beginning in the early 1960s, bipolar memory, that was, bipolar transistors, were employed.

Bob Norman was the first person that suggest the idea of using solid-state memory on an integrated circuit (IC) for the first time in 1961. In 1965, IBM made memory a common technology. On the other hand, when compared to other memory types, users found solid-state memory to be too expensive to use. Bipolar SRAM was created in the early to mid-1960s, Toshiba published DRAM in 1965, and SRAM was first used commercially in the same year. A MOS semiconductor device was used to manufacture ROM that was created in 1967 after the single-transistor DRAM cell was created in 1966. N-type MOS (NMOS) memory also began to gain popularity in the late 1960s and early 1970s.

MOS-based memory began to be widely used as a form of memory in the early 1970s. After one-year, erasable PROM was introduced in the market, and EEPROM was created in 1972.

FAQ on Computer Memory

Q1. What are the types of memories?

Ans: There are three kinds of memory:

• Primary memory
• Secondary memory
• Cache memory

Q2. What is Volatile and Non-Volatile memory?

Ans: The nature and volatility of memory mean that it is used to store information on the basis of a power supply. All of the stored data and information on this memory will be erased if the power supply is cut off. For case, Random Access Memory (RAM). On the other hand, the nature, non-volatile of memory, means that it is used to store information even while the power is off. For instance, ROM (Read Only Memory).

Q3. What is the full form of CD-ROM?

Ans: The full form of CD-ROM is compact disk read only memory.

Q4. How many 128 * 8 memory chips are needed for a memory capacity of 4096*16?

Ans: 64

Explanation:

Chips required = Required RAM size / Available chip capacity

Total Bytes = 128x8=128 bytes and4096x16=4069x(8x2) = 4096x2 bytes;

Therefore,

Number of chips required = 4096*2/128= 64

Q5. Explain any four differences between RAM and ROM?

Ans: Major four differences between RAM and ROM are given below:

Q6. How to erase data in EPROM?

Ans: With the help of using ultraviolet radiation, we can quickly erase data from an EPROM. It stands for erasable programmable read-only memory.