In 400-600 words Memory is a set of physical storage locations that are addresse
ID: 3705768 • Letter: I
Question
In 400-600 words
Memory is a set of physical storage locations that are addressed via software (programs). It is measured in kilobytes (K), megabytes (MB), gigabytes (GB), or terabytes (TB).
Remember that user memory is temporary. Memory has far less capacity than secondary storage media as in hard disks, zip drives, and CD-R. Memory has in general two parts: RAM (random access memory) and ROM (read-only memory).
Discuss the following questions and topics related to memory:
What is the classical difference between main memory and secondary memory?
Discuss with your classmates the difference between a RAM, ROM, EEPROM (electronically erasable programmable read-only memory), and DRAM (dynamic random access memory)?
What is the difference between internal cache and external cache memory?
Explanation / Answer
What is the classical difference between main memory and secondary memory?
Answer:
The classical difference between main memory and secondary memory is like short and long-term memory. The main memory is accessible by CPU while the secondary memory accessed utilizing a data bus. The main memory storing the instruction for the programs that currently being used,for instance if the computer shutoff data can no longer exits; whereas, secondary memory storing data permanently which I can access infinitely meaning data can be accessed and be available for a very long period of time
Main memory:
PRIMARY MEMORY
SECONDARY MEMORY
Discuss with your classmates the difference between a RAM, ROM, EEPROM (electronically erasable programmable read-only memory), and DRAM (dynamic random access memory)?
Answer:
RAM:
Random access memory (RAM) is a type of data storage used in computers that is generally located on the motherboard. This type of memory is volatile and all information that was stored in RAM is lost when the computer is turned off. Volatile memory is temporary memory while ROM (read-only memory) is non-volatile and holds data permanently when the power is turned off.
The RAM chip may be individually mounted on the motherboard or in sets of several chips on a small board connected to the motherboard. Older memory types were in the form of chips called dual in-line package (DIP). Although DIP chips are still used today, the majority of memory is in the form of a module, a narrow printed circuit board attached to a connector on the motherboard. The three main memory circuit boards types containing chips are: RIMMs (Rambus in-line memory modules), DIMMs (dual in-line memory modules) and SIMMs (single in-line memory modules). Most motherboards today use DIMMs.
->It is a read-write memory.
->Used to store the data that has to be currently processed by CPU temporarily
->It is a volatile memory
->Random Access Memory
->Data in ROM can be modified
->RAM is a costlier memory.
->Types of RAM are static RAM and dynamic RAM
ROM:
Read-only memory (ROM) is a type of storage medium that permanently stores data on personal computers (PCs) and other electronic devices. It contains the programming needed to start a PC, which is essential for boot-up; it performs major input/output tasks and holds programs or software instructions.
Because ROM is read-only, it cannot be changed; it is permanent and non-volatile, meaning it also holds its memory even when power is removed. By contrast, random access memory (RAM) is volatile; it is lost when power is removed.
There are numerous ROM chips located on the motherboard and a few on expansion boards. The chips are essential for the basic input/output system (BIOS), boot up, reading and writing to peripheral devices, basic data management and the software for basic processes for certain utilities.
->It stores the instructions required during bootstrap of the computer.
->It is a nonvolatile memory.
->Data in ROM can not be modified.
->ROM is comparatively smaller than RAM.
->ROM is comparatively cheaper than RAM
->Types of ROM are PROM, EPROM, EEPROM.
EEPROM:
Electrically Erasable Programmable Read-Only Memory (EEPROM) is a stable, non-volatile memory storage system that is used for storing minimal data quantities in computer and electronic systems and devices, such as circuit boards. This data may be stored, even without a permanent power source, as device configuration or calibration tables.
If storing higher volumes of data that is static (like in USB drives), certain types of EEPROM (like flash memory) are more cost-effective than conventional EEPROM devices.
The following are the primary electrical interface categories for EEPROM devices:
EEPROM is mainly used in devices (like digital potentiometers, digital temperature sensors and real-time clocks) to save calibration or similar data that is required when the power is switched off or removed.
EEPROMs are recognized as arrays of floating gate transistors
DRAM:
Dynamic random access memory (DRAM) is a type of random-access memory used in computing devices (primarily PCs). DRAM stores each bit of data in a separate passive electronic component that is inside an integrated circuit board. Each electrical component has two states of value in one bit called 0 and 1. This captivator needs to be refreshed often otherwise information fades. DRAM has one capacitor and one transistor per bit as opposed to static random access memory (SRAM) that requires 6 transistors. The capacitors and transistors that are used are exceptionally small. There are millions of capacitors and transistors that fit on one single memory chip.
DRAM is dynamic memory and SRAM is static memory. The DRAM chips on a circuit board need to refresh every few milliseconds. This is done by rewriting the data to the module. Chips that need refreshing are volatile memory. DRAM accesses the memory directly, holds memory for a short period and loses its data when the power is shut off. SRAM is volatile memory that is static and does not need refreshing. Because SRAM is a lot faster, it is used in registers and cache memory. SRAM keeps data and performs at higher speeds than DRAM. Although SRAM is faster, DRAM is used more often on the motherboard because it is a lot cheaper to manufacture.
The three main types of circuit boards that contain memory chips are dual in-line memory modules (DIMMs), single in-line memory modules (SIMMs) and Rambus in-line memory modules (RIMM’s). Today the majority of motherboards use DIMMs. The module refresh rate for DRAM is every few milliseconds (1/1000th of a second). This refreshing is done by the memory controller located on the chipset of the motherboard. Because refresh logic is used for automatic refresh, a DRAM circuit board is quite complex. There are different systems used for refreshing but all methods require a counter to keep track of the row that needs to be refreshed next. The DRAM cells are organized in a square collection of capacitors, typically 1024 by 1024 cells. When a cell is in the “read” state, an entire row is read out and the refresh is written back. When in a “write” state, a whole row is “read” out, one value is changed, and then the whole row is rewritten. Depending on the system, there are DRAM chips that contain a counter while others systems rely on a peripheral refresh logic which includes a counter. DRAM’s access time is around 60 nanoseconds, while SRAM can be as low as 10 nanoseconds. As well, DRAM’s cycle time is a lot longer than SRAM’s. The cycle time of SRAM is shorter because it does not need to stop between accesses and refreshes.
What is the difference between internal cache and external cache memory?
Answer:
Internal cache:
A level 1 cache (L1 cache) is a memory cache that is directly built into the microprocessor, which is used for storing the microprocessor’s recently accessed information, thus it is also called the primary cache. It is also referred to as the internal cache or system cache.
L1 cache is the fastest cache memory, since it is already built within the chip with a zero wait-state interface, making it the most expensive cache among the CPU caches. However, it has limited size. It is used to store data that was accessed by the processor recently, critical files that need to be executed immediately and it is the first cache to be accessed and processed when the processor itself performs a computer instruction
In more recent microprocessors, the L1 cache is divided equally into two: a cache that is used to keep program data and another cache that is used to keep instructions for the microprocessor. Some older microprocessors, on the other hand, make use of the undivided L1 cache and uses it to store both program data and microprocessor instructions.
It is implemented with the use of static random access memory (SRAM), which comes in different sizes depending on the grade of the processor. This SRAM makes use of two transistors per bit. The two transistors form a circuit known as a 'flip-flop’ since it has two states it can flip between; the second transistor manages the output of the first transistor. For as long as power is supplied to the circuit, it can hold data without external assistance.
All L1 cache designs follow the same process; the control logic of the L1 cache stores frequently used data in the cache and only updates external memory when the CPU hands over control to other bus masters when peripheral devices are doing direct memory access.
external cache:
An external cache is any cache memory or type of central processing unit (CPU) cache that is housed, placed or installed external to a computer processor.
It provides high speed data storage and processing services to the computer processor, its primary/native cache and the main memory.
External cache is also known as secondary cache
External cache is part of the main random access memory (RAM) or an independent component installed on the motherboard. Some external caches are built and integrated on the processor dye itself, but not directly the part of it.
It serves as an intermediate memory between the processor and RAM. External cache is implemented in several layers - all providing different speeds and capacity levels. For example, L2 and L3 caches are common examples or layers of external cache. A L2 cache is faster but has less storage capacity than a L3 cache