Seagate ST-506 User manual

·ST506 MICROWINCHESTER
OEM MANUAL
PRELIMINARY
APRIL 1.1 1981
·&agate Tec1moloyy

Page
4.0
Electrical
Interface
4.1
Control
Input Lines
16
4.1.1
Reduced Write
Current
17
4.1.2
Write Gate
17
4.1.3 Head Select 20
and 21
17
4.1.4
Direction
In
17
4.1.5
Step
17
4.1.6 Drive
Select
1-4 19
4.2 Control Output Lines
19
4.2.1
Seek
Complete
19
4.2.2
Track
~
19
4.2.3
write
Fault
19
4.2.4
Index
20
4.2.5
Ready
20
4.3 Data Transfer Lines
20
4.3.1
MFM write Data
21
4.3.2 ·MFM Read Data
23
4.3.3
Read/Write
Timing
23
4.4
Drive
Selected
24
4.5 CUstomer
Options
24
4.5.1 Radial Select
24
4.5.2
Defeat Reca1ibrate 24
4.5.3 Half Step
25
.5.0 Physical
Interface
26
5.1
Jl/Pl Connector -
Control Signals
27·
5.2
J2/P2 Connector -
Data Signals
28
ii

6.0
5.3
5.4
Physical
6.1
6.2
6.3
6.4
J3/P3 Connector - DC Power
J4/p4 Frame Ground Connector
Specifications
Mounting
Orientation
Mounting
Holes
Physical
Dimensions
Shipping Requirements
7.0
Track
Fonnat
7.1
7.2
7.3
7.4
7.5
7.6
Figures:
l.
2
3
4
5
6
7
8
9
10
Gap 1
Gap 2
Gap 3
Gap 4
Sector Interleaving
Defective Sector Flags
Air Fil.tration System
Positioning Mechanism
Power Up Sequence
Control Signals
Data Signals
Typical Connection, 4 Drive System
Control Receiver/Driver Combination
Step Mode T~ing
Index Timing
Data Line Driver/Receiver Combination
iii
. Page
28
30
30
30
30
30
30
33
31
31
35
35
35
35
5-6
7
9
13
14
15
16
18
20
21.

Figures (Continued)
11 Write Precompensation Patterns
12 Read/Write Data Timings
13 Connector Physical Locations
14 Jl Connector Dimensions
15 J2 Connector Dimensions
16 J3 Connector
17 Mounting Physical Dimensions
18 OVerall Physical Dimensions
19 Track Format As Shipped
20 "Al" Address Mark Byte
Tables
I Jl/Pl
Connector
pin
Assignments
II
J2/P2
Connector
pin
Assignments
III
P3 DC
Connector
Pin
Assignments
IV DC Power Requirements
iv
Page
22
23
26
27
28
28
31
32
34
35
11
12
12
29

1.0 Introduction
1.1 General Description:
The ST506 disc drive is a random access storage device with
two non-removable 5~ inch discs as storage media. Each disc
surface employs one movable head to service 153 data tracks.
The total formatted capacity of the four heads and surfaces
is 5 megabytes. (32 sectors per track, 256 bytes per sector,
612 tracks).
Low cost and unit reliability are achieved through the use
of a band actuator and open loop stepper head positioning
mechani'sm. The inherent simplicity of mechanical construction
and electronic controls allows maintenance free operation
throughout the life of the drive. Both Electronic PCB's
are mounted outside HDA for field serviceability.
Mechanical and contamination protection for the heads,
actuator and discs are provided by an impact resistant
aluminum enclosure. A self contained recirculating system
supplies clean air through a 0.3 micron filter. A second
port in the filter assembly allows pressure equalization
with ambient air without chance of contamination. A patented
spindle pump assures adequate air flow and uniform temperature
distribution throughout the head and disc area. Thermal
isolation of the stepper and spindle motor assemblies from the
disc enclosure yields a very low temperature rise within
the enclosure, providing significantly greater off track
margin and the ability to immediately perform read and write
operations after power up with no thermal stabilization delay.
The ST506 electrical interface is similar to the Shugart
Associates SAlOOO family of 8 inch fixed disc drives. The
ST506 size and mounting is identical to the industry standard
minifloppy disc drives and uses the same DC voltage and
connector. No AC power is required.
Key Features:
• storage Capacity of 6.38 megabytes unformatted, 5.0
megabytes formatted as shipped.
• Winchester design reliability, 9.5 gram head load force,
19 micro-inch flying height.
• Same physical size and mounting as the minifloppy.
• Same DC voltages as the minifloppy.
• Band actuator and stepper motor head positioning.
• 5.0 megabit/second transfer rate.
• Simple floppy like interface.
• Same track capacity as a double density 8 inch floppy.
1

•
170 millisecond random average access time, reducible to
95 ms via a simple software algorithm (See Section 4.5.3)
1.2 Specification Summary:
1.2.1
1.2.2
1.2.3
Physical Specifications:
Environmental Limits:
Ambient Temperature = 40
0
to l22
0F
(4
0
to SOOC)
Relative Humidity = 8 to SO%
Maximum Wet Bulb = 7SO non-condensing
Maximum Altitude = 10,000 feet
DC Power Requirements
+12V ~ 5%, 1.SAtypical, 4.SA at power on
+5V ~ 5%, 0.7A typica1# 1.0A maximum
+12V/+SV Maximum Ripple = 50mV P-P
Mechanical Dimensions:
Height
=
3.25
inches
Width
=
S.75
inches
Depth
=
S.OO
inches
Weight
=
4.2 1bs.
(1.9 kg)
Heat Dissipation - 25 watts typical
- 29 watts maximum'
Reliability Specifications:
MTBF = 11,000 POH, typical usage
PM = Not required
MTTR 30 minutes
Component Design Life = 5 years
Error Rates:
Soft read errors
*Hard read errors
Seek errors
= 1 per 10~~ bits read
= 1 per 10
6
bits read
= 1 per 10 seek
*Not recoverable within 16 re-tries.
Performance Specifications:
2

Capacity
1.2.4
Unformatted
Per Drive
Per Surface
Per Track. -
Formatted
Per Drive
Per Surface
Per Track
Per Sector
Sectors per Track
6.38 Megabytes
1.59 Megabytes
10416 Bytes
5.0 Megabytes
1.25 Megabytes
8192 Bytes
256 Bytes
32
Transfer Rate
5.0 Megabits per second
Access Time
Track to Track 3 ms
Average (Inc. Settle)l70 ms, reducible to 95 ms. (See Section 4.5.3)
Maximum (Inc. Settle)500 ms, reducible to 245 ms. ..
Settling Time 15 ms
Average Latency
Functional Specifications
Rotational speed
Recording density
Flux density
Track density
Cylinders
Tracks
R/W Heads
Disks
8.33ms
3600
7690
7690
255
153
612
4
2
rpm
+ 1%
bpi
max
fci
tpi
2.0 Functional Characteristics
2.1 General Operation
The ST506 disc drive consists of Read/Write and control
electronics, read/write heads, track positioning actuator,
media, and air filtration system. The components perform
the following functions:
1. Interpret and generate control signals.
2. Position the heads over the desired track.
3. Read and write data.
4. Provide a contamination free environment.
3

2.2 Read/Write and Control Electronics
Electronics
are packaged on two printed circuit boards.
The primary board to which power, control and data signals
are connected includes:
1. Index ~etection circuit.
2. Head position/actuator circuit.
3. Read/write circuits.
4. Drive up to speed circuit.
5. Head select circuit.
6. Write fault detection circuit.
7. Step motor drive circuit.
8. Drive select circuit.
9. Track zero detector circuit.
The second PCB., mounted to the baseplate under the primary
board derives. its power from the primary board and provides
power and speed control to the spindle drive motor.
2.3 Drive Mechanism
A Brushless DC drive motor rotates the spindle at 3600 rpm.
The spindle is driven directly with no belt or pulley being
used. The motor is thermally isolated from the baseplate to
minimize temperature rise in the sealed chamber containing
the heads and discs. The ~otor and spindle are dynamically
balanced to insure a low vibration level. A brake is used
to provide a fast stop to the spindle motor when power is
removed. The baseplate is shock mounted to minimize
transmissibility of vibration to the chassis or frame.
2.4 Air Filtration System (Figure 1)
The discs and read/write heads are fully enclosed in a module
using a integral recirculation air system with an absolute
filter which maintains a clean environment. Integral to the
filter is a port which also permits pressure equalization
with the ambient air without contaminate entry.
2.5 . Positioning Mechanism (Figure 2)
The read/write heads are mounted on a ball bearing supported
carriage which is positioned by a band actuator connected to
the stepper motor shaft. The stepper motor is thermally
isolated from the baseplate to minimize temperature rise in
the sealed chamber containing the heads and discs.
4

AIR fLOW
- SCRU,1313IN G
FtL TER
FIG IA
5
DISC

SCR US 131N G
F1LTER
/ . I3A R 010 ETR Ie
- FILTER ..
FIG \8
6
/
DISC
/
I
I
'-- SPINDLE
A
:: c ~ tv1 13 LY
~-' -