Search results
Results From The WOW.Com Content Network
There are four major storage levels. [1] Internal – Processor registers and cache. Main – the system RAM and controller cards. On-line mass storage – Secondary storage. Off-line bulk storage – Tertiary and Off-line storage. This is a general memory hierarchy structuring. Many other structures are useful.
Tertiary storage or tertiary memory [7] is a level below secondary storage. Typically, it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device according to the system's demands; such data are often copied to secondary storage before use. It is primarily used for archiving rarely ...
A direct-access storage device (DASD) (pronounced / ˈ d æ z d iː /) is a secondary storage device in which "each physical record has a discrete location and a unique address". The term was coined by IBM to describe devices that allowed random access to data, the main examples being drum memory and hard disk drives. [1]
An illustration of the write amplification phenomenon in flash-based storage devices. Over time, advancements in central processing unit (CPU) speed has driven innovation in secondary storage technology. [7] One such innovation, flash memory, is a non-volatile storage medium that can be electrically erased and reprogrammed.
RAM drives use normal system memory as if it were a partition on a physical hard drive rather than accessing the data bus normally used for secondary storage. Though RAM drives can often be supported directly in the operating system via special mechanisms in the OS kernel, it is generally simpler to access a RAM drive through a virtual device ...
The IBM 2315 disk cartridge stored 1 megabyte of data. An early disk cartridge was a single hard disk platter encased in a protective plastic shell. When the removable cartridge was inserted into the cartridge drive peripheral device, the read/write heads of the drive could access the magnetic data storage surface of the platter through holes in the shell.
Hard disk drives were introduced by IBM in 1956, [5] and were the dominant secondary storage device for general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern era of servers and personal computers , though personal computing devices produced in large volume, like mobile phones and tablets , rely on ...
Magnetic sequential access memory is typically used for secondary storage in general-purpose computers due to their higher density at lower cost compared to RAM, as well as resistance to wear and non-volatility. Magnetic tape is a type of sequential access memory still in use; historically, drum memory has also been used.