For as long as there has been computing, there has been a need to store the information produced by computing as memory. In this blog, we will explore a brief history of computer memory, from its origins to modern day.

The first type of computer memory took the form of paper punch cards. Punch cards were first used in 1725 in the textile industry, to control the mechanized textile looms. In the 1890s, Herman Hollerith used punch cards for census calculation for determining the population of the United States. Essentially a thick sheet of paper with holes punched through it, patterns could be imprinted on the punch card that could be interpreted by a machine. Later, they were used as an input device for computers up to the 1970s.

In 1932, magnetic drums were first created to store memory, and used up to the 1950s and 1960s as the main working memory for computers, giving them the nickname “drum machines.” Their capacity clocked in at a whopping 10 kB.

In the 1950s, paper tape, the evolution of punch cards, was developed. Instead of a card, paper tape consists of a long strip of paper, with holes punched at various locations to represent data.

After paper came magnetic tape, which worked in the same manner but could store more information. Stored in a roll similar to film and read/written by a read/write head, it is one of the oldest technologies for data storage still in use, due to its high capacity, low cost, and long durability.

In 1956, IBM released the first hard disk drive, the Model 350 Disk File, that came with the IBM 305 RAMAC computer. With 50 24-inch wide discs, it could store about 5 MB of data. The size of those discs was part of why the RAMAC weighed over a ton.

Philips introduced the first compact audio cassette in 1963. Originally intended for dictation machines, they became popular for distributing music, an aspect that Sony’s Walkman (released in 1979) helped push even further. Cassettes were also used for data storage on personal computers in the 1970s and 80s, with a storage capacity of about 660 kB per side on a 90-minute tape.

The floppy disk, introduced in 1971, was an alternative to buying expensive hard drives. The first 8-inch floppy disk had a storage capacity of 79.7 kB and was read-only, with the rewritable version following a year later. Floppy disks remained prevalent until the 1990s, where they were ultimately replaced by…

The compact disc, which was first developed in 1982. The concept of the CD went back to 1960, when James T. Russel thought of using light to record and replay music, but it took several decades for the concept to get support. By encoding tiny pits of digital data into the bottom of the discs, CDs could store far greater amounts of information.

In 1995, the Digital Video Disc, or DVD, was developed by Panasonic, Philips, Sony, and Toshiba as a faster alternative to the compact disc and could store multimedia data like movies and video.

Five years later, the Universal Serial Bus series of flash drives were invented by Israeli company M-Systems. USB drives have since become one of the most popular forms of digital memory storage, with almost every electronic device designed with USB ports in mind.


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Memory in a computer is any hardware that can store data for any amount of time. If a computer memory is volatile, the information stored on the hardware is lost after the power source is disconnected. In contrast, non-volatile computer memory retains the stored information. Under these two broad categories are many subtypes of memory.

RAM (Random Access Memory)

RAM allows the user to access any part of the memory in the same amount of time. It is used to store the programs and data being used by the central processing unit (CPU) in real time. The data can be read, written, and erased any number of times.

DRAM (Dynamic Random-Access Memory)

DRAM is a volatile memory. The information is lost within a couple of seconds of the system shut off. The bits of the memory are stored in the small circuit.  In DRAM there is just one transistor and one capacitor. Capacitors slowly lose some of their charge, so a timer circuit delivers an electrical charge to the capacitor every few milliseconds.

SRAM (Static Random-Access Memory)

SRAM loses the data almost instantaneously after system shut off. A SRAM circuit is arranged in a flip-flop design which maintains the correct charge state for the entire time that the memory is connected to power. Although SRAM is by design the faster type of memory, it does come with a higher price tag than DRAM and is therefore not as popular.

ROM (Read Only Memory)

ROM is a type of non-volatile computer memory. It usually comes in the form of a chip located on the motherboard.  Data is not lost after the system is shut down. ROM is used for firmware such as system startup programs. You cannot add or modify this type of memory. Manufacturers write the memory; however, subtypes of ROM have been developed to allow user modification.

PROM (Programmable Read Only Memory)

The data is written after the memory chip has been created. The setting of each bit is locked by a fuse or antifuse, which means that PROM can only be programmed once after creation before the information becomes permanent.

EPROM (Erasable Programmable Read Only Memory)

As the name suggests, EPROM can be erased and rewritten. EPROM is used for applications where the data needs to be frequently changed. It can be identified by the quartz crystal window that exposes the chip to ultraviolet light used to reprogram the chip.

EEPROM (Electrically Erasable Programmable Read Only Memory)

This type of memory can be erased and reprogrammed repeatedly through the application of higher than normal electrical voltage. It is used for storing minimal data quantities that need to be changed regularly. The nature of this type of memory results in a shorter life span than other computer memories.

Flash Memory

Flash memory falls into the category of non-volatile memory. Invented by Toshiba, flash memory is a specific type of EEPROM that is programs and erases data in terms of blocks. Flash memory is used for easy and fast information storage in computers and various other electronic devices. It is a portable memory that acts almost like a hard drive.


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A DIMM (Dual Inline Memory Module) is comprised of a series of dynamic random-access memory integrated circuits. This small piece of technology has the fascinating ability to provide central memory storage and data directly to the CPU it is in tandem with. It was evolved from its predecessor, the SIMM, and is capable of maintaining double the data path at 64-bit. The DIMM is also twice as small, leaving room for other components within the CPU.    

With only one circuit board installed on the DIMM (dual in-line memory module), it substantially increases both memory speed and storage. It is manufactured with 168 pins which enable them to connect to the CPU’s motherboard with ease. On the bottom edge of each one of these pins lies two notches. The location of each notch designates a certain feature of the module. The first notch facilitates the dynamic random-access memory utilizing a high-bandwidth interface. The second notch corresponds to the voltage position. 

DIMM is not strictly limited to PCs as it can be applied on a wide range of electronic products including networking hardware, netbooks, and printers. The versatility of this technology adds to its impressive capabilities. The command address and control signals are buffered on the DIMMs as well. This buffering reduces the loading efforts of the memory function in Cabin Dome Lts Dimm.

The more DIMM slots your motherboard has, the more RAM you can install. Motherboards support anywhere from one to eight DIMM slots, however, most mainstream motherboards have four. You may be asking yourself, how many DIMM slots do you actually need? The answer to this question depends on how much RAM storage you desire. 32GB worth of RAM-which is more than enough-can be achieved with two DIMM slots.

DIMMs are available in four variations: SDR (single data rate), DDR (double data rate), DDR2, and DDR3. The DDR2 and DDR3 are the upper echelon in terms of capabilities and potential.

Before selecting which version of DIMM is best suited for your motherboard, consult your motherboard documentation for the correct memory speed and type for your system. If a system requires a specific speed for the memory module, a substitute with faster speeds is almost always able to function the same if the specified one isn’t available.


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In the current age of technology, the motherboard is arguably one of the most commonly recognized computer components. Often pictured as a green, square circuit board panel, this device, in tandem with a few other main components, allows modern computer systems to accomplish specific calculations and tasks on behalf of various industries. From aircraft avionics systems to your desktop at home, a computer is typically made up of the same four components— motherboard, central processing unit (CPU), hard drive, and a random-access Memory (RAM) module.

The CPU operates as the “brains” of a computer system. It handles detailed, complex processing and organizes data that is exchanged within a computer’s central unit. Its main job is to direct components on the motherboard to access data stored in the hard drive or RAM, and process said data according to the task it needs to perform. If you’ve ever heard the term “dual-core” processor, which is a commonly used type of CPU, this term refers to the number of cache cores that a computer system is utilizing within its CPU. Cache units allow the CPU to speed up it's processing by “caching” information that is pulled from the RAM or hard drive. The CPU is a binary system and can only exchange this data on a separate data bus and address bus. In simpler terms, the address bus knows where to find information within the RAM or hard drive duplicators and sends it back to the core processor via the data bus.

A motherboard acts similarly to a “central nervous system”, as it is a centralized location that links the entire information network within a central unit. The motherboard works directly with a CPU to process data and channel the data through a printed circuit that is connected to controls within the system. Most contain over 30 components, all of which operate at the same MHz thanks to an internalized quartz clock that is installed on the motherboard. This clock ensures all information exchanged between components is transmitted at the same digital pulse rate, regardless of the pre-existing MHz of every separate component. The parts achieve this through a multiplying device, which adjusts the MHz of the component to that of the quartz oscillator.

The hard drive and RAM operate as long-term and short-term memory storage devices. Both save data, but in different ways and for different purposes. A hard drive saves data that needs to be used on a long-term basis, including operating systems, installed programs, personal files, etc. Commonly used hard drives include the solid-state drive (SSD), classical, and external.

RAM modules can contain a number of RAM chips, which store temporary data while the computer is operating. It only stores memory temporarily— when the computer turns off, RAM data is completely wiped.  This unit is particularly useful because it helps speed up information processing during high data events such as imagery or GPS navigation tracking system. If you had to reload each aspect of an entire map every time a vehicle moved by tapping into the hard drive instead of the RAM, it would take much longer to update a navigation system.

At Expedited Quoting, owned and operated by ASAP Semiconductor, we can help you find all the cable modems and memory cards you need, new or obsolete. As a premier supplier of parts for the aerospace, civil aviation, and defense industries, we’re always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at sales@expeditedquoting.com or call us at +1-857-323-5480.


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One of the most important aspects to consider when looking for a new computer is probably the memory. In Computer memory, the storage space in the computer where data is processed and stored, making it one of the determining factors in how well your computer performs. In general, there are two types of computer memory: primary memory and secondary memory.           

Primary memory is the computer memory that is directly accessed by the central processing unit (CPU). When you turn your computer on, the primary memory loads the operating system, user interface, and all other software utilities. Every application-specific task is carried out thanks to the interaction between the primary memory and the system processor. There are two types of primary memory: RAM and ROM.

RAM, or Random-Access Memory, is a volatile-type memory that stores data temporarily in specific memory slots. RAM allows the computer to read and write data near instantaneously, making it a very fast and responsive type of memory. The more RAM your computer has, the more data you can load, and the better your computer performs overall. However, the same principles that make it so fast are what makes it volatile; because the data is stored temporarily, when the computer is turned off, the data is lost. Within RAM, there is Dynamic RAM (DRAM), Static RAM (SRAM), Direct Rambus RAM (DRDRAM), Synchronous Dynamic RAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), and their respective successors.

ROM, or Read-Only Memory, is a non-volatile-type memory that retains all data in permanent memory slots. Because the data is permanently stored, no data is lost when the computer is turned off. Typically, ROM is unalterable, so it’s used to store firmware, which has little to no necessary updates or changes. However, recent advances in memory technology means that there are such things as Programmable ROM (PROM), Erasable Programmable ROM (EPROM), and Electrically Erasable Programmable ROM (EEPROM).

Secondary memory, as opposed to primary memory, is an external computer memory that is permanent. This is where data and programs are saved for longer periods of time. The data can be altered and changed, but they are “permanently” stored in secondary memory media. Secondary memory also tends to have much larger capacities compared to the computer’s primary memory. Hard Drive Disks (HDD), magnetic disks, magnetic tapes, Solid State Drives (SSDs), and USB memory drives are all examples of secondary memory.

Without primary memory, the CPU cannot access the necessary data fast enough for the user to use applications or programs smoothly. If the CPU had to access data from secondary memory like the hard drive, then the computer becomes so slow that it’s essentially useless. But, at the same time, primary memory is so limited in how much space it can have while still being quick and efficient, hence the need for slower but larger secondary memory. Next time you go shopping for a computer, think about what type of work you’ll be using it for— that will determine how much memory you need.

At Expedited Quoting, owned and operated by ASAP Semiconductor, we can help you find all the computer memories and RAM modules you need, new or obsolete. As a premier supplier of parts for the aerospace, aviation, and defense industries, we’re always available and ready to help you find all the parts and equipment you need, 24/7x365. For a quick and competitive quote, email us at sales@expeditedquoting.com or call us at +1-857-323-5480.



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When operating any type of equipment from a cell phone to a jet plane, you’re provided with the status information of the equipment or machinery in question.  For example, your cell phone constantly tells you what the battery life is at and how much cell signal you get. Your car tells you how much fuel is left, how fast you’re driving, etc. As the sophistication of the equipment increases, so does the need for accurate and reliable instrumentation.

This is undoubtedly true for aviation. Aircraft pilots need to be able to confidently rely on the provided information to maintain safe flight.  There are three main classifications of aircraft instrumentation: flight instruments, engine instruments, and navigation instruments

Flight instruments are paramount to the operation of the aircraft.  Flight instruments parts include an altimeter for altitude; a magnetic direction indicator, which a type of compass; and an airspeed indicator.  Additional instruments include an artificial horizon indicator and various other such indicators. These indicators are typically placed in the center of the console or display for visibility to the pilot and co-pilot. 

Engine instruments are essential information that must be relayed to the operator continuously.  Engine instruments include: fuel indicator; fuel pressure; oil levels and oil temperature; inlet and exhaust temperatures; manifold pressure; etc. Multi-engine aircraft often have duplex gauges that display multiple independent readings.  Constant monitoring of the engine instruments is paramount, especially because we rely on the engines to get us from point A to point B.

Navigation instruments are used to maintain and guide pilots on their desired course.  Radio waves used to be the biggest part of navigation, now the integration of the Global Positioning System (GPS) is much more common because it offers accurate and reliable information. 

These days, there’s been a digital takeover of the cockpit, often replacing analog instruments for a display screen.  This advancement in technology is great for decluttering the cockpit.  But simple analog instruments are still used for redundancy in the event of electrical issues.  These reliable flight instruments are operated by air pressure and gyroscopes. 

Expedited Quoting, owned and operated by ASAP Semiconductor, is a premier supplier of aircraft instrument parts and avionics components. Whether new or obsolete, we can help you find all the parts you need, 24/7x365.  If you’re interested in a quote, email us at sales@expeditedquoting.com or call us at +1-857-323-5480.


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