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Hardware Disk Drive

ND 574

288 MBYTE DISK DRIVE

INTRODUCTION

The ND 574 288 Mbyte Disk Drive is a high performance high capacity random-access storage device which uses a removable disk pack for recording data. Data is stored on 19 surfaces. One surface is used for servo-head word positioning.

FEATURES

  • Low average access time
  • High data transfer rate
  • Daisy-chaining of up to four drives on ND 559 and ND 632 Disk Controllers
  • Automatic retries whenever recording errors are encountered
  • ECC as standard, for increased reliability
  • Media and interface compatibility with other manufacturers
  • Standard quiet cabinet

PRODUCT DESCRIPTION

The basic disk unit consists of a disk spindle with an associated drive motor, an actuator assembly, speed and position sensing devices, and logic circuitry for positioning, reading and writing.

A hinged cover allows access to the spindle for pack installation and removal, while also providing a seal in the closed position to maintain cleanliness within the disk shroud.

The disk controllers - ND 559 and ND 632 - take care of the data transfers between one of a maximum of four disk drives and memory. An eight Kb FIFO buffer is employed to allow instantaneous DMA traffic to be larger than the maximum channel bandwidth. This is done by buffering disk data to and from memory.

ECC is standard for ND 559 and ND 632, and is capable of 34-bit burst error detection and 11-bit burst correction within each sector (512 words).

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Technical Specifications

Positioning Time

  • Maximum: 55 ms
  • Average: 30 ms
  • One track: 6 ms

Latency Time

  • Maximum: 17.2 ms
  • Average: 8.33 ms

Access Time

(positioning and latency time): - Maximum: 72.2 ms - Average: 38.33 ms

Number of Cylinders

  • 823

Number of Sectors per Track

  • 18

Number of Tracks per Cylinder

  • 19

Net Capacities per:

  • Sector: 512 words
  • Track: 9216 words
  • Cylinder: 175104 words

Unit ND 574

  • 144.110592 Mwords (288 Mbytes)

Transfer Rate

  • Bit rates: 9.677 mHz
  • Word rates: 604 kHz

Maximum Numbers of Units per Controller

  • ND 559: 4
  • ND 632: 4

Media

  • 288 Mbyte Disk pack: ND 575

Power Requirements

  • Voltage AC:
    • 220V ± 15 / -15
    • 240V ± 17 / -17
  • Watts:
    • 1500 operating
    • 350 standby
  • Hertz: 50 ± 0.5 - 1.0

Temperature

  • Operating: 15°C to 40°C
  • Gradient: 6.7°C/hour

Humidity

  • Operating: 20% to 80% non-condensing

Size

  • Height: 91.4 cm
  • Width: 58.4 cm
  • Depth: 91.4 cm
  • Weight: 321 kg

Documentation

  • Disk Drive Operator Guide
    • (ND art.number 750742): Control Data