Subject: RK02/03 Documentation

From: [email-masked] (Ronald Copley)
Date: 1 Jul 94 11:09:32 EDT

(NOTE: contains all the typographical errors of the original!)

DECPACK DISK CARTRIDGE SYSTEM - RK11-C/RK02, RK03

1. Introduction

The DECpack cartridge disk drive and control is a complete mass storage

system, offering an economical solution for large volume, random-access

data storage. The system includes a modular mass storage device

utilizing removable disk cartridges and a complete easy-to-program

control.

The DECpack is available in two models:  The RK02 drive with over

600,000 words per drive; and the RK03 drive with over 1.2 million words

of storage per drive.

The DECpack is ideal where a large volume of programs and data are

developed and maintained for one or more users. When used with PDP-11

software such as the Disk Operating System or RSTS-11 System, DECpack

offers the flexibility of permitting each member of a group of users to

maintain his own private program and data files. It is expandable up to

4.8 million words (RK02) or 9.6 million words (RK03) per controller.

2. Operation

The removable disk cartridge offers the flexibility of virtually

unlimited off-line capacity with rapid transfers of files between

on-line and off-line without copying operations. It utilizes a cartridge

similar to the IBM 2315, but with 12 sectors.

Average total access time on each drive is 90 milliseconds. On expanded

systems, operations are overlapped for efficiency; one drive may read or

write while one or more additional drives are seeking new head positions

for the next transfer. All data transfers utilize the Non-Processor

Request facility during transfers.

Each disk is permanently mounted inside a protective case that

automatically opens when inserted in the disk drive. While on-line, dust

contamination is prevented by a highly-efficient continuous "absolute"

air filtration system.

The DECpack provides accurate data storage and transfers by means of a

write check function, correct cylinder verification by hardware,

hardware checksum, and hardware maintenance features. There are no

mechanical detents, thus a major source of wear and critical adjustment

is eliminated.

3. Programming

    REGISTER                                    ADDRESS

    Drive Status Register (RKDS)                777400

    Error Register (RKER)                       777402

    Control Status Register (RKCS)              777404

    Word Count Register (RKWC)                  777406

    Current Bus Address Register (RKBA)         777410

    Disk Address Register (RKDA)                777412

    Maintenance Register (RKMR)                 777414

    Data Buffer Register (RKDB)                 777416

 Drive Status Register (RKDS)

 Contains the current selected drive status and current sector address.

 It is a read only register.

    BIT     NAME                                DESCRIPTION

    15-13   Ident. of Drive(ID)         If an interrupt is caused as a

                                        result of a SEARCH COMPLETE (Bit

                                        13 RKCS) or a SEEK INCOMPLETE

                                        (Bit 9 RKDS) these bits will

                                        contain the binary

                                        representation of the logical

                                        drive number that caused the

                                        interrupt.

    12      Drive Power Low(DPL)        Set when an attempt is made to

                                        initiate a new function was

                                        actively in progress when the

                                        control sensed a loss of power

                                        to one of the disk drives. This

                                        bit is normally accompanied by

                                        bit 15 RKER(DRE) and is reset by

                                        a BUS INIT or a CONTROL RESET

                                        function.

    11      High Dens. Drive(HDEN)      Set to identify the selected

                                        disk drive as an RK03 and reset

                                        to identify the selected disk

                                        drive as an RK02.

    10      Drive Unsafe(DRU)           Indicates that an unusual

                                        condition has occurred in the

                                        drive and it is unable to

                                        properly perform any operations.

                                        Putting the RUN/LOAD switch in

                                        the LOAD position will reset the

                                        condition. If, upon putting the

                                        RUN/LOAD switch back to the RUN

                                        position the condition reoccurs

                                        the drive or associated power

                                        supply is inoperative and

                                        corrective maintenance

                                        procedures should be begun.

                                        Normally accompanied by bit 15

                                        RKER.

    9       Seek Incomplete(SIN)        Indicates that due to some

                                        unusual condition a SEEK

                                        function was not completed

                                        within 180ms of initiation. A

                                        DRIVE RESET function clears this

                                        condition. This bit is normally

                                        accompanied by bit 15 RKER.

    8       Sector Counter OK(SOK)      Indicates that the selected

                                        drive sector counter (Bits 0-3

                                        RKDS) is not in the process of

                                        changing and is ready for

                                        examination.

    7       Drive Ready(DRY)            Indicates that the selected disk

                                        drive is in the following

                                        condition:

                                        a) properly supplied with power

                                        b) loaded with a disk cartridge

                                        c) door is closed

                                        d) LOAD/RUN switch is in the RUN

                                           condition

                                        e) the disk is spinning

                                        f) the heads are properly loaded

                                        g) the disk is not in a DRU

                                           condition (Bit 10 RKDS).

    6       Access Ready(ARDY)          Indicates that the selected

                                        drive head mechanism is not in

                                        motion and the drive is ready to

                                        accept a new function.

    5       Write Protect Status(WPS)   Set when the selected disk is in

                                        WRITE PROTECTED mode.

    4       Sect. Counter=Sect. Addr.   Indicates that the disk heads

                                        are positioned over the disk

                                        addresses currently held in bits

                                        0-3 RKDA.

    3-0     Sector Counter(SC)          Indicates the current sector

                                        address of the selected drive.

                                        This is the look ahead and will

                                        work for any disk cartridge with

                                        up to 16 sectors. Sector address

                                        00 is defined as the sector

                                        which follows the sector that

                                        contains the index pulse. This

                                        is an important consideration

                                        when using the R/W ALL mode of

                                        operation.

Error Register (RKER)

(This is a read only register)

    BIT     NAME                                DESCRIPTION

    15      Drive Error(DRE)            Set when an attempt is made to

                                        initiate a function, or when a

                                        function is actively in

                                        progress, while the selected

                                        drive is not ready or in some

                                        error condition or if any of te

                                        dirves in the system senses a

                                        loss of either AC or DC power.

                                        If this bit is found set the

                                        RK03 should immediately be

                                        referenced to discover the cause

                                        of the condition.

    14      Overrun(OVR)                During a READ, WRITE, RD/CHK or

                                        WT/CHK, operations on sector 13,

                                        surface 1 of cylinder address

                                        312, were finished and the RKWC

                                        had not yet overflowed. This

                                        essentially is an attempt to

                                        overflow out of a disk drive.

    13      Write Violation(WLO)        Set if an attempt is made to

                                        write on a disk which is

                                        currently being write protected.

    12      Seek Error(SKE)             Set if the disk head mechanism

                                        is not properly positioned while

                                        executing a normal READ, WRITE,

                                        RD/CHK or WT/CHK function.

    11      Programming Error(PGE)      The R/W ALL bit (Bit 9 RKCS) or

                                        the RMT bit (Bit 10 RKCS) were

                                        set while initiating some

                                        function other than a READ or

                                        WRITE.

    10      Non-Existent Memory(NXM)    Set if memory does not respond

                                        within 20us of the time when the

                                        RK11 becomes Bus Master during a

                                        DATI or DATO NPR sequence.

                                        Because of the speed of the RK03

                                        disk drive, it is likely that if

                                        a NXM does occur it will be

                                        accompanied by a DLT (Bit 7

                                        RKER).

    9       Data Late(DLT)              Set when an NPR sequence is

                                        initiated before the previous

                                        one has completed.

    8       Read Timing Error(RTE)      Two or more consecutive read

                                        clock pulses were dropped by the

                                        disk drive.

    7       Non-Existent Disk(NXD)      An attempt was made to initiate

                                        a function on a non-existent

                                        drive.

    6       Non-Existent Cylinder(NXC)  An attempt was made to initiate

                                        a function on a cylinder larger

                                        than 312.

    5       Non-Existent Sector(NXS)    An attempt was made to initiate

                                        a transfer on a sector larger

                                        than 13.

    4-2     Unused

    1       Checksum Error(CSE)         Set while performing a RD/CHK or

                                        READ function as a result of

                                        faulty recalculation of the

                                        checksum. Cleared at the

                                        initiation of any new function.

                                        This is a soft error.

    0       Write Check Error(WCE)      Indicates that an error was

                                        encountered during a WT/CHK

                                        function as a result of faulty

                                        bit comparison between disk data

                                        and memory data. Clears at the

                                        initiation of a new function.

                                        This is a soft error.

    Note:  Bits 5 through 15 are all hard errors. They clear only by a

    BUS INIT or a CONTROL CLEAR function.

Control Status Register (RKCS)

    BIT     NAME                        DESCRIPTION

    15      Error                       Set when any bit in the RKER is

                                        set. Processor reaction is

                                        dictated by Bits 6 and 8 RKCS.

                                        This read-only bit clears if all

                                        the bits in the RKER are cleared

                                        and if Bit 14 RKCS is cleared.

    14      Hard Error(H.E.)            Set when any of Bits 5-15 RKER

                                        are set by the control. Stops

                                        all controller action and

                                        processor reaction as dictated

                                        by bit 6 RKCS. This READ ONLY

                                        bit, along with bits 5-12 RKER,

                                        is cleared only by a BUS INIT or

                                        a CONTROL RESET function.

    13      Search Complete(SCP)        Signifies that the prvious

                                        interrupt was caused as a result

                                        of some previous SEEK or DRIVE

                                        RESET function. READ ONLY bit.

                                        Clears at the initiation of any

                                        new function.

    12      Maintenance Mode            When set, will inhibit any

                                        signals from being transmitted

                                        to or from any disk drive and

                                        will permit diskless operation

                                        of the RK11. Used in conjunction

                                        with the RKMR.

    11      Inhibit Inc.(INH BA)        Setting this bit inhibits

                                        incrementing the RKBA during a

                                        data transfer. Tis allows data

                                        to be transferred to or from any

                                        one bus address for the entire

                                        operation.

    10      Format(FMT)                 FORMAT Mode must be used only in

                                        conjunction with the normal READ

                                        and normal WRITE function. This

                                        mode is used to format a new

                                        disk pack or to reformat any

                                        sector that may have been erased

                                        or damaged due to control or

                                        drive failure.

                                        In the FORMAT mode the normal

                                        WRITE operation is altered only

                                        in that the servo positioner is

                                        not checked for proper position

                                        before the write operation.

                                        Under a normal WRITE the header

                                        is re-written each time the

                                        associated sector is written. In

                                        this mode, the normal READ

                                        operation is altered in that

                                        only one word is transferred to

                                        memory per sector; the header

                                        word. Therefore, a 3-word READ

                                        function in the FORMAT mode will

                                        transfer 3 contiguous header

                                        words to 3 consecutive memory

                                        locations for software checking.

                                        For a 200-word transfer, 200

                                        consecutive header words from

                                        200 consecutive sectors will be

                                        read, and so on.

    9       Read Write All(R/W A)       Must be used only in conjunction

                                        with a READ or WRITE function.

                                        The drive performs part 1 of a

                                        normal SEEK function after which

                                        it searches for SC = SA. When

                                        found, the read amplifiers or

                                        write drivers are turned on and

                                        every 16-bits a word is

                                        transferred to or from memory

                                        until the RKWC overflows. This

                                        mode is used to simulate formats

                                        to be written or read on

                                        controllers other than the RK11.

    8       Stop on Soft Error(SSE)     If a soft error is encountered

                                        while this bit is set:

                                        a. and Bit 6 RKCS (IDE) is

                                        reset, all controller action

                                        will stop at the end of the

                                        current sector.

                                        b. and Bit 6 RKCS (IDE) is set,

                                        all controller action will stop

                                        and a Bus Request will occur at

                                        the end of the current sector.

    7       Control Ready(RDY)          Signifies that the control is no

                                        longer engaged in actively

                                        executing a function and is

                                        ready to accept a command.

    6       Int. on Done Enable(IDE)    The control will issue a Bus

                                        Request and interrupt to vector

                                        address 220 if:

                                        1. A function has completed its

                                        activity;

                                        2. A hard error is encountered;

                                        3. A soft error is encountered

                                        and bit 8 RKCS is set.

    5-4     Memory Extension(MEX)       Reserved for extended bus

                                        addresses and is used in

                                        conjunction with the RKBA. These

                                        bits make up a two-bit counter

                                        that increments each time the

                                        RKBA overflows. A bus DATO to

                                        these bits overrides any

                                        overflow from the RKBA. They are

                                        read/write.

    3-1     Function                    These bits indicate the binary

                                        representation of the function

                                        to be performed.

                                        The functions are:

                                        CONTROL RESET (000)

                                        WRITE (010)

                                        READ (010)

                                        WRITE CHECK (011)

                                        SEEK (100)

                                        READ CHECK (101)

                                        DRIVE RESET (110)

                                        WRITE LOCK (111)

    0       Go                          Write only bit. Indicates the

                                        function encoded in bits 1

                                        through 3 of RKCS. Stays set

                                        until one control actually

                                        begins to respond to the go

                                        command.

Word Count Register (RKWC)

    Contains the two's complement of the total number of words to be

    affected by a given function. It increments by one after each word

    transfer.

Current Bus Address Register (RKBA)

    Contains the Bus Address to or from which data will be transferred.

    The register is incremented by two at the end of each transfer.

Disk Address Register (RKDA)

    BIT     NAME                        DESCRIPTION

    15-13   Drive Select(DR SEL)        Contains binary representation

                                        of the logical drive number

                                        currently being selected.

    12-5    Cylinder Address(CYL ADD)   Contains binary representation

                                        of the cylinder address

                                        currently being selected. The

                                        largest valid number is 312.

    4       Surface(SUR)                When active lower disk head is

                                        enabled.

    3-0     Sector Address(SA)          Binary representation of the

                                        disk sector to be addressed.

    This register may be loaded only while the RK11 is in the ready

    state.

Maintenance Register (RKMR)

    This register is provided for diagnostic purposes only and does not

    participate in the normal disk operations.

4. Cross Cylinder Operation

Surface 0 is defined as the upper surface and is active when RKDA 04 is

reset. If a tranfer is initiated that requires overflow from surface 0,

the control will automatically change to sector 0 or surface 1. If a

transfer is initiated that requires an overflow from surface 1, the

control will automatically move the heads to the next contiguous

cylinder, check for proper head positioning, and continue the transfer

on sector 0 and surface 0 of the new cylinder. An attempt to overflow

out of the last secotr of te last cylinder will result in an error

condition.

At the end of any transfer the RKDA is automatically incremented.

5. Hardware Poll

The control is capable of having any or all of the drives performing a

SEEK or DRIVE RESET operation at any one time. A HARDWARE POLL feature

will identify the logical drive number in bits 13, 14 and 15 of the RKDS

of any drive that has completed a SEEK or DRIVE RESET operation and

cause an interrupt if bit 6 RKCS is set (IDE) and the control is in the

READY state (bit 7 RKCS is set) and the control was not already

attempting to cause an interrupt as a result of some other operation.

Tis will occur even if Bit 6 RKCS (IDE) was not set when first

initiating the SEEK or DRIVE RESET function. If two or more drives

complete the function simultaneously, the control will interrupt once

for each drive and identify each one in turn in the RKDS. Care should be

taken in this situation to raise the processor interrupt status to

level equal to or greater than that currently held by the RK11 or else a

second interrupt will occur immediately after the first and the end

result will be that the interrupt service routine has been interrupted.

This situation will also occur if an attempt is made to initiate a SEEK

to an address that the drive is already at since one interrupt will

occur as a result of the SEEK or DRIVE RESET function having been

successfully initiated and another to report that the heads have reached

their destination, which will occur immediately because the heads are

already there.

6. Interrupts

Because of the format structure of the RK11-C, any interruption of a

write sequence cannot be tolerated until the end of the sector because

this would result in essentially an unformatted disk. Therefore, any

outside interventioin of this operation is held off until the end fo the

current sector, which includes the CONTROL RESET function and the

PROCESSOR or BUS INITIALIZE signals. Therefore, all those functions,

such as CONTROL RESET, SEEK and WRITE LOCK, which normally take only a

few microseconds to initiate can actually take up to 3.3ms if initiated

while writing. For this reason the SEEK and WRITE LOCK functions will

cause an interrupt (if bit 6 RKCS is set) as soon as the function has

been succesfully initiated. The CONTROL RESET, which cannot cause an

interrupt under any cirumstance, can, therefore, take up to 3.3ms to

complete.

7. Specifications

                                RK02 Drive              RK03 Drive

1 disk/drive

203 cylinders/drive:            128 data words/track    256 words/track

2 surfaces/drive:               1536 data words/track   3072 words/track

12 sectors/track:               307,200 data            614,400 data

                                words/surface           words/surface

1 to 8 drives/control:          614,400 data            1,228,800 data

                                words/drive             words/drives

            Access Times (including head settling; typical)

Track to track:                 15ms

Average random move:            70ms

Average rotation delay:         20ms

Data Transfer Rate:             22.2 usec per word for RK02 drive

                                11.1 usec per word for RK03 drive

Transfer Path:                  Non-Processor Request (NPR)

                                Direct Memory Access

Minimum Block Size:             One sector (128 words for RK02 drive;

                                256 words for RK03 drive)

Minimum Transfer:               1 word

Density:                        1100 BPI max. for RK02 drive

                                2200 BPI max. for RK03 drive

Speed:                          1500 RPM

Environmental Requirements:     60 to 90 F and 20% to 80% relative

                                humidity

                                Model Designations

Control:                        RK11-CA 117V +10% 50/60Hz

                                RK11-CB 235V +10% 50/60Hz

Bus Priority Level:             BR5

Interrupt Vector Address:       220

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