internal hard disc model WDS-2120
Date: 1993
Inventory Number: 2004-1-0012
Classification: Hard Drive
Maker: IBM Japan Ltd (founded 1937)
User: Apple Computer Inc. (1976-present)
Cultural Region:
City of Use:
Dimensions:
10.2 × 7 × 1.7 cm (4 × 2 3/4 × 11/16 in.)
Accessories: re-usable grey plastic sleeve
DescriptionThe hard disc drive is stored in a reusable grey plastic, static protective sleeve. The hard disc mechanisms are housed in a rectangular black plastic case. The case has a green plastic cutout circuit board, with several mounted and soldered microchips and circuit components on the back. The circuit board permits the drive to communicate with a computer to which it is attached. Along one short edge of the circuit board is a white plastic strip with 24 brass pins emerging from it with which the board would be connected to a computer.
Inside the disc drive, but obscured from view by the black casing and circuit board, is what is called the "platter" of the hard disc. It is a stack of large, flat, circular discs. Each disc is constituted of a non-magnetic material (usually glass or aluminum alloy) encased in a very thin layer of magnetic material. The platter is mounted on a cylindrical metal spindle at the center that can spin the platter for reading and writing data. A motor is housed inside the spindle to power the spinning. The disc drive is also equipped with a metal arm, called the "actuator arm". The very tip of the arm, called the "head" is equipped with the read/write mechanism for storing data on the platter discs. The actuator arm is connected to an "actuator axis" that controls its movements as directed by the computer through the circuit board.
Inside the disc drive, but obscured from view by the black casing and circuit board, is what is called the "platter" of the hard disc. It is a stack of large, flat, circular discs. Each disc is constituted of a non-magnetic material (usually glass or aluminum alloy) encased in a very thin layer of magnetic material. The platter is mounted on a cylindrical metal spindle at the center that can spin the platter for reading and writing data. A motor is housed inside the spindle to power the spinning. The disc drive is also equipped with a metal arm, called the "actuator arm". The very tip of the arm, called the "head" is equipped with the read/write mechanism for storing data on the platter discs. The actuator arm is connected to an "actuator axis" that controls its movements as directed by the computer through the circuit board.
Signedprinted in black and white letters on a white and black label on instrument casing: [black apple logo] Apple Computer Inc. / Internal HDD Firmware © 1993 / 120 MB 2.5" SCSI 17mm / Designed and Manufactured / to Apple Specifications / IBM OEM SA 9U / MODEL: WDS-2120 CS / RATED -: 5.0V VOLTAGE - DC / Made by IBM Japan LTD.
Inscribedprinted in black lettering underneath barcode on white label on instrument casing: G0304537 0000 GS0
printed in black lettering on white label in instrument casing: P/N : 95F7189 / FRU P/N: / MLC : 023543
printed in black lettering underneath barcode on white label on instrument casing: *IB3051X0E*
printed in black lettering around circumference of round white sticker on instrument case: * WARRANTY VOID IF SEAL IS BROKEN
printed in black lettering on brown label on grey instrument bag: ATTENTION / Static-Sensitive / Devices / Handle Only at / Static-Safe / Workstations / Reusable / Container / Do Not Destroy / JEDEC-14/Symbol
in black lettering on white label on instrument circuit board: 4491
printed in black lettering on white label in instrument casing: P/N : 95F7189 / FRU P/N: / MLC : 023543
printed in black lettering underneath barcode on white label on instrument casing: *IB3051X0E*
printed in black lettering around circumference of round white sticker on instrument case: * WARRANTY VOID IF SEAL IS BROKEN
printed in black lettering on brown label on grey instrument bag: ATTENTION / Static-Sensitive / Devices / Handle Only at / Static-Safe / Workstations / Reusable / Container / Do Not Destroy / JEDEC-14/Symbol
in black lettering on white label on instrument circuit board: 4491
FunctionHard discs are a mechanism for storing digital information. Information is read and written on the platter by an actuator arm stored within. Each platter disc is subdivided into many very small magnetic regions. Each region can have a magnetic field of one of two directions, analogous to the 1s and 0s of digital binary logic. The head of the actuator arm inside reads and writes the direction of magnetic regions to store and retrieve data. Hard discs are called "hard" because of the rigid material used to make the platter. They are most often connected to a computer, acting as the primary memory center. The circuit board is the mechanism by which this hard disc was connected to a computer. This device was manufactured by IBM Japan Ltd. for use in an Apple personal computer.