Wang System 2200 User manual

WANG 2200
Model 2280/2280N
Disk Diive User Manual

2200
Model 2280/2280N
Disk Drive
User Manual
Copyright ®Wang Laboratories, inc., 1979
700-521 6C
WANG
WANG LABORATORIES, INC., ONE INDUSTRIAL AVENUE, LOWELL, MA 01851 'TEL: [phone]. TWX710-343-S769. TELEX 94-7421

Disclaimer of Warranties
and Limitation of Liabilities
The staff of Wang Laboratories, Inc., has taken due care in preparing
this manual; however, nothing contained herein modifies or alters in any
way the standard terms and conditions of the Wang purchase agreement,
lease agreement, or rental agreement by which this equipment was
acquired, nor increases in any way Wang's liability to the customer. In no
event shall Wang Laboratories, Inc., or its subsidiaries be liable for inci-
dental or consequential damages in connection with or arising from the
use of this manual or any programs contained herein.
Warning: This equipment generates, uses, and can radiate radio fre-
quency energy and, if not installed and used in accordance with the
instructions manual, may cause interference to radio communications. It
has been tested and found to comply with the limits for aClass A
computing device pursuant to Subpart Jof Part 15of FCC Rules, which
are designed to provide reasonable protection against such interference
when operated in acommercial environment. Operation of this equipment
in aresidential area is likely to cause interference in which case the user
at his own expense will be required to take whatever measures may be
required to correct the interference.
WANG
WANG LABORATORIES, INC., ONE INDUSTRIAL AVENUE, LOWELL, MA 01851 •TEL. [phone], TWX 710-343-6769, Telex 94-7421

HOWTO USE THIS MANUAL
This manual provides information concerning the operation of the Model
2280/2280N series disk drives. It is intended to be used in conjunction with
the Wang BASIC-2 Disk Reference Manual .
Chapter 1discusses the concept of information storage and retrieval on
the disk, including an overview of the disk hardware and the principles of
disk operation. Chapter 2provides specific operational data, including
power-on and formatting procedures. Disk drive specifications £uid maintenance
information are collected in the appendices.
Ill

TABLE OF CONTENTS
CHAPTER 1GENERAL INFORMATION
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
CHAPTER 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Introduction
The Disk Processing Unit (DPU)
Random Access Data Storage
The Disk Platter
Sectors on the Disk Platter
Track and Sector Numbering on the Disk Platter ..
Disk Access Time
Addressing the Model 2280/2280N
MOUNTING AND FORMATTING INSTRUCTIONS
Unpacking and Inspection
Installation •••
Model 2280/2280N Operating Procedures
Power On Procedure
Controls and Indicators
Loading and Unloading the Removable Disk Platter .
Disk Cartridge Removal
Loading aNew Disk Cartridge
Handling and Storage of the Removable Disk Platter
Model 2280/2280N Formatting Instructions
Error Correcting Code (ECC)
1
4
5
5
6
6
7
8
9
9
11
11
11
12
12
15
17
17
18
APPENDICES
Appendix AModel 2280/2280N Specifications ..
Appendix BDisk Platter Maintenance Information
Appendix CEquipment Guarantee and Prevention
Maintenance Information
INDEX
19
21
24
25
XV

FIGURES
1-1 Model 2280/2280N Disk Drive 1
1-2 Model 2280/2280N Disk Drive Fixed and Removable Platters .... 3
1-3 Model 2280/2280N Disk Unit Read/Write Heads 4
1-4 Concentric Tracks on aDisk Platter with Enlarged View
of Several Tracks Showing How Information Is Stored 5
1-5 Cross-section of aDisk Platter Showing Track Numbering
on the Upper and Lower Surface 6
1-6 Sector Numbering on aModel 2280-1 /2280N-1 Disk Surface 7
2-1 Model 2280/2280N Series System Configuration 10
2-2 Model 2280/2280N Dual System Configuration 10
2-3 The Model 2280/2280N Control Panel 12
2-4 Opening the Access Door 13
2-5 Removing the Disk Cartridge 13
2-6 Locking the Cartridge onto the Dust Cover 14
2-7 Carrying aSealed Cartridge 14
2-8 Loading the Disk Cartridge 16
2-9 The Wrong Way to Load the Disk Cartridge 16
2-10 Closing the Access Door 16

CHAPTER 1
GENERAL INFORMATION
1.1 INTRODUCTION
The Model 2280/2280N series of Fixed/Removable Disk Drives is
specifically designed for the customer who has large data storage
requirements. Each of the Model 2280/2280N series of disk drives contains
approximately 13.4 megabytes of removable storage and up to 67.0 megabytes of
fixed storage, depending upon the model designation. Three versions of the
Model 2280/2280N are available: the 2280-1 (2280N-1) ,the 2280-2 (2280N-2) ,
and the 2280-3 (2280N-3) ,with total storage capacities of approximately 26.8,
53.6, and 80.4 megabytes respectively.
To speed processing and provide extensive error correction, the disk
units are controlled by an intelligent Disk Processing Unit (DPU) which can
support two drives. One DPU is included in the price o£ a2280 disk unit. A
Model 2280N disk drive, identical to aModel 2280 in all other respects, is
shipped without aDPU and is intended for use as the second drive on aDPU.
Up to three 2280 DPU's, with amaximum of two drives each, may be attached to
a2200 system (the 2200T, PCS-II, PCS-III, and WCS-15 excluded).
Figure 1-1. Model 2280/2280N Disk Drive

In a standard configuration (see Figure 2-1) ,one Model 2280 disk drive
is connected to the DPU. The DPU is attached to the 2200 Series Central
Processing Unit (CPU) via astandard Model 22C03 disk controller. In adual
system configuration (see Figure 2-2) ,a2280N disk drive is cabled to the
2280 disk drive, and its output lead is connected to the DPU. Both disk units
may thereby be controlled by the same DPU.
The Model 2280/2280N Disk Drives contain up to four disk platters
mounted horizontally on asingle drive shaft. The platters are mounted one
above the other, somewhat as phonograph records are stacked on arecord
changer (see Figure 1-2) .The top disk platter is housed in acartridge which
can be removed from the disk unit and replaced; it is therefore referred to as
the removable disk platter. Because it is contained in asealed,
cartridge-like casing to protect it from damage when it is removed from the
disk unit, the removable platter is also sometimes referred to as adisk
cartridge. The other three disk platters are positioned below the removable
platter on the shaft. As an integral part of the disk unit, they cannot be
removed, suid are therefore called the fixed disk platters. The shaft itself
is coupled to adrive motor which spins the disk platters at aconstant speed
of 3600 rpm.
Information is recorded on, or read from, the surface of adisk platter
via the read/write head. The read/write heads are attached to acomb-type
access assembly consisting of four access arms (see Figure 1-3) .The
read/write head is fixed in position and cannot move independently of the
access arm.
When adisk statement or commamd is executed from the system CPU, the
access assembly moves the read/write heads in and out over the surface of the
disk platters as they rotate. Aread/write head CcUi then record (write)
information on asurface of adisk platter or retrieve (read) information from
aplatter as the platter rotates past the head's position.
The fixed platters can contain up to five recording surfaces with one
track servo surface; the removable platter contains one surface which is a
recording surface and one which is atrack servo surface. Aservo surface
contains prerecorded information that is used by the drive electronics to
position the read/write heads to the desired track. (The number of recording
surfaces accessible in each Model 2280/2280N disk unit is shown in the
following table.)

Recording Surfaces on the Model 2280/2280N
Model Number of Recording
Surfaces
2280-1 or 2280N-1 1Removable, 1Fixed
2280-2 or 2280N-2 1Removable, 3Fixed
2280-3 or 2280N-3 1Removable, 5Fixed
Removable Disk Platter
Lower Surface
Fixed Disk Platter
Lower Surface
Fixed Disk Platter
Lower Surface
Fixed Disk Platter
Lower Surface
Fixed Disk Platter
Upper Surface
Rxed Disk Platter
Upper Surface
Figure 1-2. Model 2280/2280N Disk Drive Fixed and Removable Platters