The 2301 attaches to a System/360 through an IBM 2820 Storage Control Unit, which might control as a lot as four 2301s. The 2311 mechanism is largely similar to the 1311, but recording improvements allow higher data density. The 2311 shops 7.25 megabytes on a single removable IBM 1316 disk pack consisting of six platters that rotate as a single unit. The 2311 has ten particular person read/write (R/W) heads mounted on a typical actuator which moves out and in hydraulically and is mechanically detented on the desired monitor before studying or writing occurred. Each recording floor has 200 tracks plus three elective tracks which can be used as alternate options in case faulty tracks are found. This technology and its derivatives remained the standard by way of 2011.
Average entry time was sixteen ms. Purchase value at time of introduction ranged from $81,000 to $142,200. Due to tribology issues encountered between heads and media, the first models did not ship till October 1981. Access time is 25 millisecond and information transfers at 885 kB/s.
It additionally suffered from a number of serious compatibility points . A higher density, 1.07 GB, version was included into the 9333 subsystem in May 1992. The 3390 Model 9 was the last Single Large Expensive Disk drive announced by IBM. Could have any particular feature included that the master drive has integrated. In 1984, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers.
Unlike true random entry gadgets, the time to entry a document on a direct entry system does depend somewhat on its handle on the gadget. In order to learn a report in the middle of the tape, the read/write heads have to be moved over the entire data that precede the goal document. This chapter presents an overview of 1 member of a class of units that may be known as “permanent, secondary storage”.
Developed on the IBM Rochester, MN, laboratory as the 21ED it was an 8-inch HDD with an preliminary capability of 15 or 30 MB in 2 or mm disks. In 1983 it shipped as the HDD in the 5360 System Unit of the S/36. In 1984 its capability was doubled by doubling the number of tracks per surface and it was integrated into the 5362 System Unit of the System/36. Packaged in Hard Disk Assemblies with 2 actuator-head items and one set of platters, a model 1 HDA provides 1.89 GB before formatting and a model 2 supplies three.78 GB/HDA. The IBM 3340 Direct Access Storage Facility, code-named Winchester, was launched in March 1973 for use with IBM System/370.