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Attached DASD A-units: The 3990 Model 1 can attach up to four 3380 A-units. The 3390 Models 2, 3 and 6 can intermix up to four 3380 and 3390 A-units; Cache: In the Models 3 and 6 one director has a cache and one director has nonvolatile storage; The Model 1 can be field upgraded to a Model 2 or 3.
An early public use of the acronym DASD is in IBM's March 1966 manual, "Data File Handbook. [7]" The earliest non-IBM use of the acronym DASD found by the "Google ngram viewer" to refer to storage devices dates from 1968. [8] From then on use of the term grew exponentially until 1990 after which its usage declined substantially. [9]
Block diagram of count key data track format used on IBM mainframe computers beginning with S/360 shipment in 1965. The reason for CKD track format is to allow data field lengths to vary, each recorded block of data on a DASD track, called a record has an associated count field which identifies the record and indicates the size of the key, if used (user-defined up to 255 bytes), and the size ...
All the preceding DASD models are equipped with a large AC motor, driving the HDA with a belt; however, the 3390 HDA is directly driven by a DC motor that is included in the enclosure. The 3390 Model 9 was the last Single Large Expensive Disk (sometimes called SLEDs) drive announced by IBM.
Virtual Storage Access Method (VSAM) [1] is an IBM direct-access storage device (DASD) file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now in z/OS.
IBM System/360 Model 20 CPU with front panels removed, with IBM 2560 MFCM (Multi-Function Card Machine) IBM System/360 Model 30 CPU (red, middle of picture), tape drives to its left, and disk drives to its right, at the Computer History Museum IBM System/360 Model 50 CPU, computer operator's console, and peripherals at Volkswagen System/360 Model 65 operator's console, with register value ...
On February 15, 1988, IBM announced [18] Processor Resource/Systems Manager (PR/SM) for 3090 enhanced ("E") models This feature allows the operator to define and assign resource to a virtual machine known as a logical partition (LPAR). Initially there was a 4-LPAR limit for uniprocessors and an 8-LPAR limit for multiprocessors, but newer ...
Gene Amdahl was against this and wanted to develop a faster single processor. Things came to a head in 1979, and Amdahl left the company in August to start Trilogy Systems . [ 12 ] With Gene Amdahl's departure, and increasing influence from Fujitsu , Amdahl entered the large-scale multiprocessor market in the mid-1980s with the 5860, 5870 ...