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Computer Memory
The computer memory is a physical device used to store data or programs for use in a computer. Some types of computer memory include RAM (random access memory), ROM (read-only memory), and page cache.
4,434 Questions
The POST is a program essentially and it's "located" on the motherboard. The software gets run when you first turn the computer on.
How many types of RAM are there?
Dynamic Random Access Memory(DRAM):-
- contents are constantly refreshed 100times per second.
- Access time 60-70 nanoseconds.
- quicker than DRAM
- access time than 60 nanoseconds.
- new type of ram architecture.
- access time is 20 times faster than DRAM.
- more expensive.
- doesn't need refreshing.
- retains contents as long as power applied to the chip.
- access time is around 10 nanoseconds.
- used for cache memory, CPU registers.
- CMOS SRAM also data and time settings, powered by small battery.
- small amount of memory typically 256 kilobytes to 32 megabytes (depending on computer).
- temporary storage for often used instructions and data
- cpu checks to see whether the next instructions it requires in cache.
- if not the cpu has to fetch next information from the main memory.
- Often implemented in multiple levels: L1I/L1D, L2, L3, etc.
- holds the data that can be displayed on the computer.
- Has two data paths allowing to READ & WRITE to occur at same time
- a graphics card may have its own VRAM chip on board.
- contents are retained even without power
- read cycles are similar to SRAM
- unfortunately write cycles are about 100 times slower than read cycles
- due to this read/write timing asymmetry, these are more commonly used as "solid state disks" like Compact Flash, SD cards, "USB pen drives", etc. than as normal computer memory
- contents are retained even without power
- implemented as and SRAM with Flash Memory backup storage
- at power on, internal circuits copy the Flash Memory to the SRAM all bits at the same time in one cycle
- while power is on the SRAM is accessed as normal
- when a signal is received from the powersupply warning that power is turning off, internal circuits copy the SRAM to the Flash Memory all bits at the same time, however as the Flash Memory write time is much longer than its read time this powersupply warning signal must significantly precede actual loss of power at the NOVRAM chip.
- contents are retained even without power
- has been considered obsolete since about 1980
- even with automated machine assembly these still required significant hand labor to build
- contents are retained even without power
- Integrated circuits intended to replace DRAM are still in development
What are your memories of September 11 2001?
memories when 11 September 2001 attack is mostly the world trade center and the deaths of those people who died on that day
They are either plated with tin or gold.
What is the minimum number of bits required to represent the following decimal number 101000?
17 bits would allow a value up to 131071.
What are two major categories of static RAM memory?
What_are_two_major_categories_of_static_RAM_memory
What things have been used for storing computer data?
In the early days of computers efficient, fast, and reliable mechanisms for storing data were basically unknown and mostly had to be invented from scratch.
Ideally the memory should involve a minimum of electronics, permit random access anywhere in the same period of time, and require little maintenance to prevent data corruption in operation at a relatively low cost per memory location. However given the state of electronics at the time, there were many aspects of these requirements that conflicted.
Sequentially accessed memories are much simpler, reliable, and lower cost than randomly accessed memories but access time is variable and usually longer than randomly accessed memories. Therefore many early computers used various types of sequentially accessed memory: rotating capacitor drum dynamic memory, mercury tank acoustic wave delay line dynamic memory, rotating multiple fixed head magnetic drum memory, rotating multiple fixed head single platter magnetic disk memory, magnetostrictive delay line dynamic memory, etc.
The early randomly accessed memories were all based on vacuum tubes: Williams-Kilburn tube (CRT) dynamic memory, various type of "flood gun" CRT static memories, Selectron tube static memory, etc. However these systems either had high maintenance costs or manufacturing the special vacuum tubes (e.g. Selectron tubes) proved impractical.
The first truly practical randomly accessed memory system developed used ferrite magnetic cores. This was not only static but also nonvolatile memory, thus offering significant advantages over earlier memories. Ferrite magnetic core memories rapidly replaced all earlier computer memory systems (except in the very lowest cost systems where very low cost sequentially accessed memories continued in use), and dominated the computer main memory and buffer memory markets for over 20 years.
Intel developed the semiconductor DRAM (i.e. the 1103) in 1970, a randomly accessed solid state dynamic memory chip. By about 1975 various semiconductor DRAM chips had replaced all earlier computer main memory types. The cost per bit was very low and has continued to drop, while memory sizes have essentially grown exponentially over time.
In terms of bulk storage (often offline, requiring operator action to make it available to the computer), many early computers used decks of punchcards or rolls of punched paper tape, but these were slow and the paper could wear out over time becoming unreadable.
Magnetic tape was introduced on the UNIVAC i (i.e. nickel plated bronze strip) in 1951 and IBM 701 (i.e. iron oxide coated cellulose acetate strip) in 1952 which was much faster, higher data capacity, and more reliable than the punchcard or paper tape storage.
IBM introduced the first movable head magnetic hard disk (i.e. the IBM 350) in 1956, this has gone through many improvements since then and in various forms now dominates most of bulk data storage market.
Photostore optical memory was the first bulk storage with a capacity exceeding one billion bits, however it involved large complex high maintenance mechanical systems to write and read the small film cards the data was recorded on.
Digital CDs and DVDs have been used for ROM for several years, but writable ones are also available.
Semiconductor Flash memories were introduced in the 1990s and although originally only used as electronically reprogrammable ROM, improved versions are now beginning to replace magnetic hard disks.
There are also many other things that have been tried as memories over time, with varying degrees of success (and frequently failure), but listing all of these would be far beyond the scope of this site and would involve writing several books. Many of them are "minor" variants on systems mentioned above.
How do you fix the horn 2001 dodge ram?
CHECK # Remove the cover from the power distribution center and check the relay and fuses # Disconnect the electrical connector from the horn # Have an assistant press the horn button and use a voltmeter to make sure there is battery voltage at the dark green/red wire of the connector if the relay is god and theres no voltage at the horn the wire which leads to the relay has a fault # Use a ohmmeter to measure the resistance between the wiring connector black wire and a good ground.There should be zero ohms # If theres voltage at the horn and the wiring circuits are good the horn is faulty REPLACEMENT # Disconnect the electrical connector remove the mounting bolt and detach the horn
It could be, but many modern computers have 8GB or more, that is 8 million KB!
The amount of memory a given computer may have could be written in B, KB, MB, GB, etc. by using the appropriate binary-metric prefix.
Examples:
- 128B the internal RAM of a simple microcrontoller
- 64KB the typical memory of an early 1980s microcomputer
- 2.7MB the amount of memory required to save a photo
- 12GB memory of a modern laptop computer
- 256GB memory of a modern supercomputer
- etc.
However prior to 1964 when IBM released their line of System 360 computers and defined the byte as being 8 bits, memory size was measured in many different units:
- words, used on "scientific" computers (most were binary, but a few were decimal). Typical word sizes varied from about 36 bits to 60 bits (on decimal computer words varied from about 10 digits to 18 digits) with memory sizes typically ranging from 1K words to 32K words.
- characters or digits, used on "business" computers. These systems were all decimal, characters were usually 6 bits + 1 parity bit (7 bits), digits were usually 4 bits + 1 parity bit (5 bits) with memory sizes typically ranging from 20K characters/digits to 100K characters/digits. Many business computers had variable "word" size.
What is a simplified and organized data called?
information
But the scientific name for it is usually input.
What type of data does RAM hold?
In the broadest terms, it holds both instructions (computer programs) and user data. Programs might include the operating system, games, an antivirus and a firewall program, office programs, etc.; data might include a document you are working on, images, music, etc. In all cases, long-term storage is on a hard disk or similar device - hard disks are common in the case of personal computers. The RAM temporarily holds information that has been "loaded" or "opened".
What is the name of the memory cache that is closest to the processor die but is not housed on die?
Level 2 cache (L2 cache)
What to do to not damge your cache memory for RuneScape?
"Damaging" the RuneScape cache on your computer does nothing. I frequently delete it to refresh the data which in turns boosts performance.
ROM
ROM is an acronym for Read Only Memory. The advantage of ROM is that its contents do not evaporate when the power is switched off. Therefore the program which needs to execute when the computer is first switched on is stored in a ROM chip on the computer's motherboard.
Once the program stored in the ROM chip has finished initialising the hardware, it moves the head of the hard disk to track 0, reads the first sector of track 0 into memory, and then passes control to the short program stored in the first sector of the hard disk. To simplify a bit, it is the responsibility of that program to locate the operating system files on disk, and then begin the process of loading them.
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primary memory is built in memory on a computer it is the main type of memory.... eg RAM ROM and HDD
Where can you get a replacement dash for a 2002 dodge ram?
contact Chrysler corporation they will assit you with a local dealership to replaced your cracked dashboard..
What is a stack Is it a part of RAM?
The satck is a piece of memory that is allocated on the RAM, that a thread of a computer program uses for most of its variables.
How many address lines and data lines are required for a 128k x 8 memory system?
17 address lines and 8 data lines.
2^17=128k
Answer
Processes access virtual memory space, not physical memory. Applications never access RAM directly but only through the memory management interface of the processor.
Depending on which version of Windows you are using, and how the program was compiled there is a different maximum ammount of addressable memory.
All 32 bit processes on 32bit Windows have a 4GB virtual address space. The upper 2GB is common to all processes and is used by the system. The lower 2GB is private to each process and is inaccessable to all others. Unless the program was compiled as large address aware, in which case it will have 3GB of private address space.
For 32bit processes on 64bit Windows, each process has 2GB private address space, unless compiled large address aware in which case it has 4GB private address space.
For 64bit processes on 64bit windows each process has 8TB of private address space whilst compiled as large address aware. The 2GB address space limit remains for programs not compiled as large address aware.
This is completely independent of the size of RAM or the pagefile. The system maps physical memory into this virtual address space according to both need and availability.
At any given time the data in virtual memory space might be stored in RAM, on disk, or both. All of this is totally transparent to all applications. Frequently accessed data will be kept in RAM with the remainder left on disk.
