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Hard Drive: RODIME: RO652A 21MB 3.5"/HH SCSI1 SE

R O 6 5 2 A    RODIME
NO MORE PRODUCED                                      Native|  Translation
Form                 3.5"/HH               Cylinders     306|     |     |
Capacity form/unform    21/   25 MB        Heads           4|     |     |
Seek time   / track  85.0/18.0 ms          Sector/track   34|     |     |
Controller           SCSI1 SINGLE-ENDED    Precompensation
Cache/Buffer             4 KB FIFO BUFFER  Landing Zone
Data transfer rate    0.937 MB/S int       Bytes/Sector      512
                            MB/S ext
Recording method     RLL 2/7                        operating  | non-operating
Supply voltage     5/12 V       Temperature *C        10 50    |
Power: sleep              W     Humidity     %        10 85    |
       standby            W     Altitude    km                 |
       idle          13.0 W     Shock        g        10       |     30
       seek               W     Rotation   RPM      2746
       read/write         W     Acoustic   dBA
       spin-up            W     ECC        Bit   32
                                MTBF         h      12000
                                Warranty Month
Lift/Lock/Park     NO           Certificates



 ++ LED                                          1     4 P2 |
 ++                                                         |
  |                                                         |
  |                                                         6-5
  |                                                      S1 | |
  |                                                       ++2-1
  |                                                       |||XX S
  |                                                       |||XX C
  |                                                       ++|XX S
  |                                                       ++|XX I
  |                                             Terminator|||XX
  |                                             Packs     |||XX
  |                                                       ++|XX P1
  |                                                       ++|XX
  |                                                       |||XX
  |                                                       |||XX
  |                                                       ++|XX
  +---------------------------------------------------------+2 1



Jumper Setting

x = Factory setting

   | SCSI ID  |        Jumpers        |       +-2--4--6-+
   |          |  1-2  |  3-4  |  5-6  |       | o  o  o |
   +----------+-------+-------+-------+       | o  o  o |
   | x  0     | OPEN  | OPEN  | OPEN  |       +-1--3--5-+
   |    1     | OPEN  | OPEN  | CLOSED|
   |    2     | OPEN  | CLOSED| OPEN  |
   |    3     | OPEN  | CLOSED| CLOSED|
   |    4     | CLOSED| OPEN  | OPEN  |
   |    5     | CLOSED| OPEN  | CLOSED|
   |    6     | CLOSED| CLOSED| OPEN  |
   |    7     | CLOSED| CLOSED| CLOSED|

 DC Power and pin connector assignments
 pin 1    +12 VDC
 pin 2    Ground
 pin 3    Ground
 pin 4    + 5 VDC



Drive Mounting RO 650A
A sub-frame with tapped holes is provided with each drive and permits
base or side mounting. This frame is fixed to the module via shock
absorbing mounts. The drive may be oriented in any axis. When
installing the drive into an enclosure at least 0.1 inch clearance
must be maintained around the entire drive to ensure vibration
isolation, prevent obstruction of the breather filter and the
creation of ground loops.

Screw size for RO 650A drive mounting is 6-32 inch; 0.25 inch max.
thread engagement depth.

Mounting RO 750A
The RO 750A consists of an RO 650A module and sub-frame which is
attached to additional side brackets. The complete assembly meets the
form factor requirements of a "half-height" 5.25 inch Winchester
disk drive with the same tapped mounting holes.

Screw size for RO 750A drive mounting is 6-32 UNC; 0.25 inch max.
thread engagement depth.

Multiple Drives
Up to seven drives may be radially connected to a single host
adapter. The adapter itself requires a unique SCSI address. RO 650A
assignment is achieved by placing jumpers on the SCSI selector,
designated S1. The drive is shipped with an SCSI address of 0 i.e.
no jumpers are present.

D.C. Power Connector
DC power is provided by a four pin AMP Mate-N-Lok connector (P2/J2)
part number 350211-1 mounted on the solder side of the board. The re-
commended mating connector is AMP part number 1-480424-0 utilising
AMP pins part number 350078-4.

Interface Connector
The RO 650A disk drive interface to a host adapter using a 50 pin,
nonshielded flat ribbon connector. This connector is designated J1
and connects to the drive via connector P1. The pins are numbered 1
through 50. Pin 2 is located on the end of the board furthest from
the DC power connector and is market. The recommended mating
connector is 3M ribbon connector, P/N 3425-3000.

The drive has a single LED visible through the front facia,
designated LED1. This LED will only be on when the drive is selected,
otherwise it will be off. At the end of the power-up routine the LED
will remain off.

This LED is also used to flash fatal error messages should such fault
conditions exists on the drive.

Electrical Interface
The basic operating configuration consists of a host computer, host
adapter and the RO 650A disk drive. The host is a computer system,
the host adapter is an interface between the host's bus and the disk

 All signals are active low and use open collector drivers. The bus
 should be terminated at both ends with 220 ohms to +5V and 330 ohms
 to ground at each of the cable.

Output Characteristics
Each signal driven by the RO 650A has the following output
characteristics when measured at the drive's connector:

     Signal assertion               = 0.0 volts dc to 0.4 volts dc.

     Minimum driver output capacity = 48 milliamps (sinking) at 0.5
                                      volts dc.

     Signal negation                = 2.5 volts dc to 5.25 volts dc.

Input Characteristics
Each signal received by the RO 650A shall have the following input
characteristics when measured at the drive's connector:

     Signal true                    = 0.0 volts dc to 0.8 volts dc.

     Maximum toatl input load       = -0.4 milliamp at 0.4 volts dc.

     Signal false                   = 2.0 volts dc to 5.25 volts dc.

     Minimum input hysteresis       = 0.2 volts dc.

Terminator Power (Optional)
The RO 650A is configured to supply terminator power,(TERMPWR), with
the following characteristics:

VTERM = 4.0 volts dc to 5.25 volts dc.

800 milliamps minimum source drive capability.

1.0 milliamp maximum sink capability.

Hardware Implementation
SCSI is implemented on a 50-way bus which has multiple, independent,
interchangeable slots. The main advantage of a bus is that several
tasks can be interleaved simultaneously on the bus. The RO 650A may
operate in any of the configurations shown.

Sample SCSI Configuration

            Host Adapter
   +--------+ |        +-----+ Single Initiator, Single Target
   +--------+  SCSI Bus+-----RO 650A

   +--------+  SCSI    +-----+ Single Initiator, Multiple Target
   +--------+| Bus  |  +-----RO 650A
           Host     |  +-----+
           Adapter  +--+Drive|
                       +-----RO 650A

         Host Adapter
   +--------+| SCSI Bus+-----+ Multiple Initiator, Multiple Target
   |ComputerXXX-+---+--+Drive|  +
   +--------+   |   |  +-----+  |
   +--------+   |   |  +-----+  |
   |ComputerXXX-+   +--+Drive|  +
   +--------+|      |  +-----+  |
       Host Adapter |  +-----+  |
                    +--+Drive|  +----  RO 650A Intelligent Disk Drive
                    |  +-----+  |
                    |  +-----+  |
                    +--+Drive|  +
       Host Adapter |  +-----+  |
   +--------+|      |  +-----+  |
   |ComputerXXX-----+--+Drive|  +
   +--------+          +-----+

Buffer Memory
A static 4K RAM data buffer is used as a first in first out (FIFO)
circuit. This buffer i sused to enhance drive performance by storing
blocks of data, thus allowing speed matching between the disk drive
and the host.

For convenience the default values set by Rodime are listed below:

Format Parameters
Sectors per track = 32
Bytes per sector = 532
Interleave Factor = 2

Geometry Parameters
Number of cylinders = 306
Number of heads = 4



Model Description

The RO 650A/750A represents Rodime's latest advance in innovative
techology, offering arbitrating 3.5" Winchester disk drive with SCSI
(Small Computer System Interface) and embedded drive controller,
realising 20 MB of formatted capacity.

The design is based on the field proven RO 350 and RO 650 series and
takes Winchester technology a step with further with a number of
features and benefits including a 4 Kbyte, FIFO data buffer for rapid
data transfer and complete host software device independence by
implementation of a common command set. The drive and controller use
VLSI and surface mounted component techniques to contain these
features within the standard 3.5" form factor.

Like all Rodime disk drives, the new series features rugged
construction and few internal parts, making them suitable for the
harsh environment encountered by portable computers.

The encoder/decoder provides an efficient interface between the NRZ
data required by the disk controller and 2,7 run length limited code
used in the drive. The encoder/decoder also includes address mark
generation and detection logic.

Disc Controller
The disk controller performs the basic read/write functions. For this
purpose this device provides the necessary serialisation/deseriala-
tion, formatting, ECC generation and correction functions.

Sector Level Defect Handling
The Drive maintains a list of all the media defects found during the
manufacturing process, known as the Primary Defect List or P-List.
This list can be read when using the READ DEFECT DATA command. Media
defects which occur during the life of the drive may be logically
removed vy using the RE-ASSIGN BLOCKS command. Any such defects are
appended to the Growing Defect List or G-List, which can also be read
using the READ DEFECT DATA command.

 Seek Time
       |Track-to-Track         msec. typ. |  18    |
       |Average                msec. typ. |  85    |
       |                       msec. max. | 180    |
       |Latency                msec. avg. |  10.9  |

Defect Handling Overview
Rodime undertake testing on the RO 650A/750A disk drive, using both
analogue and digital techniques, to identify suspect areas on the
disk surface. These are known as media defects and are considered to
be unreliable areas on the disk surface, for data recording purposes.
These data defects are printed on a label fixed to the top cover of
the drive. This defect map, as its known, specifies defects in terms
of cylinder, head and bytes from index. The exact location of a disk
flaw will always be the same, as index is a timing signal which marks
a fixed reference point on the drive. This same information is also
recorded on a special maintenance track on the drive.

One of the principal features of SCSI is that the host system
"perceives" any disk drive as a series of contiguous, defect-free,
logical blocks. This implies that some mechanism must exist to over-
come media defects. Although this function is mostly transparent to
the user.

Spare Sectors and Tracks
In order to implement a defect handling scheme specific sectors and
tracks on the drive are reserved as spare.

A feature of the RO650A/750A is that the sector size is variable be-
tween 128D and 4096D bytes per sector. This is user selectable by
issuing a MODE SELECT (class 0, opcode 15H) command.

Once the user selects the required sector size, the drive automatic-
ally calculates the optimum number of sectors per track, leaving one
spare sector on every track (regardless of sector size). On the RO
650A/750A this realises a total of 1024 spare sectors - 306
cylinders; 4 heads per cylinder.

Seven spare tracks are also reserved for defect handling. These
tracks are NOT a part of the logical address space normally available
to the user.

    Spare Tracks
   | Cyl.| Head  | Format     | Function      |
   | -2  |  1    | User Format| Spare Track 1 |
   | -2  |  2    | User Format| Spare Track 2 |
   | -2  |  3    | User Format| Spare Track 3 |
   | -1  |  0    | User Format| Spare Track 4 |
   | -1  |  1    | User Format| Spare Track 5 |
   | -1  |  2    | User Format| Spare Track 6 |
   | -1  |  3    | User Format| Spare Track 7 |

Sector Interleaving = 2:1

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