I REJECT CODE
4.4 INTERFACE COMMAND DESCRIPTIONS
4.4.1.7 IMPROPER COMMAND SEQUENCES
The tape area forward of a just completed write-type corrmand (WRT, WTM, ERG) is erased for a short distance. When this erasure impinges into another block, this block is partially erased.
Write-type commands followed by forward read commands are not prohibited but should be avoided or the user tape operating system should maintain knowledge of the condition.
4.4.2 No Operation (NOP) Command
Nap command operations perform essentially no function. The MTS error status outputs do not change. BUSY is asserted only for the short time necessary to accept and process the command.
Other than command initiation, no signal responses are required of the user interface.
4.4.3 Drive Clear (CLR) Command
eLR resets the OVRNS, DATA CHK, 10 BRST, CRERR, SUPER, and ERRMX error status outputs if they are asserted from the previous operation. CLR also resets SSC. The MTS remains in Online Status
if previously in that state.
The functions of a Drive Clear automatically by the MTS as the except a NOP, SNS, or OMS command.
command are always performed initial part of all commands Other than command initiation, no signal responses are required of the user interface.
4.4.4 Diagnostic Mode Set (OMS) Command
,
The DMS command causes the MTS to accept certain commands, most of which are used for diagno~tic purposes, but some of which are
tailored for functionai operation use.
Other than command initiation, no signal responses are required from the user inter·face.
The change from diagnostic mode to functional mode is accomp 1 i shed when: ( 1)· the user asser ts the Reset 1 i ne, or (2) wnen the MTS automatically transfers the mode after certain diagnostic mode. command sequences.
The diagnostic mod~ set command must be followed by the specific command desired. This second command consists of a
functional-type command AND an identifying code on SLX 2, 1, and 0 lines in the following format:
DMS/eee slx
Where eee is the command following OMS, and slx is the code on the SLX lines.
In most cases (except some parts of the OMS/NOP command), the command following the OMS command is not valid unless it comes with the proper SLX lines code. The available OMS commands are described in. the following paragraphs.
4.4.4.1 OMS/Nap (STATUS LINES TEST COMMAND)
This command initiates and sequences the status line test portion of the interface test. Following the initial Nap command which resets all s ta tus excep t the On 1 i ne S ta tus (ONLS) 1 ; ne, each subsequent Nap command results in the assertion of an individual status line (in addition to ONLS) in the order shown in Table 4- 11 .
Following the 52nd assertion of NOP, . the subsystem enters a command wrap mode. In this mode the host may issue any command (with START assertl0ns) with SLX lines 2, 1, and 0
=
XXX. for each subsequent START assertion, BUSY i~ set and the individual incoming command lines are mapped to the outgoing status lines shown in Table 4-12. This mode of operation is maintained until a reset command is iSSUed. Functional operations can proceed only after·a reset conmand is issued.4.4.4.2DMS/WRT (SLX 2, 1,
a =
000) (WRITE IN PLACE COMMAND)For the MTS without the Cache Buffer, this command results in a
function~l write but with tape positioning such that the rewrite occurs at the same place. This command is used in a diagnostic write error recovery sequence which attempts to i~olate media as the cause of tef1llorary errors. This command is intended to follow a failing WRT, BSB command sequence. Only the WRT ilTl1lediately following the OMS occurs at the ~ame place.
For the MTS with the Cache Buffer, this command is functional only in long-record mode.
Table 4-11. Status Line Assertion For OMS/NOP Command Sheet 1 of 2
Nap SLX 1
NO. 210 ASSERTED STATUS
°1 XXX
2 XXX Identification Burst Status o( 010 Burst) 3 XXX File Protect Status (FPTS)
4 XXX Rewinding Status (RE1NS)
5 XXX Expecting Data Status (RECV)
6 XXX Operation Incomplete Status {no \
....
. . 1'1'" TMr\ f.., I AAI\. vvv None, except ONLS
8 XXX Tape MarK Status (TMS)
9 XXX
I
Overrun Status (OVRNS)
10 XXX Data ChecK Status (DATA CHK) 11 XXX EPROM Error Status (ROMPS)
41"1
XXX Corrected Error Status (CRERR)
I~
13 XXX None, except ONLS
14 XXX High Density Status (HDNS) 15 XXX Ready Status (RDYS)
16 XXX Write Status (WRTS)
17 XOO MUX Byte 0 Bit 0 (ERRMX 0) 18 XOO MUX Byte 0 Bit 1 (ERRMX 1 ) 19 XOO MUX Byte O. Bi t 2 (ERRMX 2)
20 XOO MUX Byte 0 Bit 3 (ERRMX 3) 21 XOD MUX Byte 0 Bit 4 (ERRMX 4) 22 XOD MUX Byte 0 Bit 5 (ERRMX 5) 23 XOD MUX Byte 0 Bit 6 (ERRMX 6) 24 XOO MUX Byte 0 Bit 7 (ERRMX 7 )
25 XOO MUX Byte 0 Bit P (ERRMX P) 26 XOl MUX Byte 1 Bit 0 (ERRMX 0) 27 XOl MUX Byte 1 Bit 1 (ERRMX 1 ) 28 X01 MUX Byte 1 Bit 2 (ERRMX 2) 29 XOl MUX Byte 1 Bit 3 (ERRMX 3 ) 30 X01 MUX Byte 1 Bit 4 (ERRMX 4) 31 XOl MUX Byte 1 Bit 5 (ERRMX 5) 32 X01 MUX Byte 1 Bit 6 (ERRMX 6) 33 XOl MUX Byte 1 Bit 7 (ERRMX 7 ) 34 XOl MUX Byte 1 Bit P (ERRMX P) x
=
do not careTable 4-11. Status Line Assertion For OMS/NOP Command Sheet 2 of 2
NOP SLX
NO. 210 ASSERTED STATUS
35 X10 MUX Byte 2 Bit 0 (ERRMX 0) 36 X10 MUX Byte 2 Bit 1 (ERRMX 1) 37 X10 MUX Byte 2 Bit 2 (ERRMX 2) 38 X10 MUX Byte 2 Bit 3 (ERRMX 3) 39 X10 MUX Byte 2 Bit 4 (ERRMX 4) 40 X10 MUX Byte 2 Bit 5 (ERRMX 5) 41 X10 MUX Byte 2 Bit 6 (ERRMX 6) 42 X10 MUX Byte 2 Bit 7 (ERRMX 7)
43 X10 MUX Byte 2 Bit P (ERRMX P) 44 X11 MUX Byte 3 Bit 0 (ERRMX 0)
45 X11 MUX Byte 3 Bit 1 (ERRMX 1) 46 X11 MUX Byte 3 Bit 2 (ERRMX 2) 47 X 11 MUX B~te 3 Bit 3 (ERRMX 3) 48 X 11 MUX By-te3 Bit 4 (ERRM-X 4)
49 X 11 MUX Byte 3 Bit 5 (ERRMX 5) 50 X 11 MUX Byte 3 Bit 6 (ERRMX 6) 51 X 11 MUX Byte 3 Bit 7 (ERRMX 7)
52 X 11 MUX Byte 3 Bit P (ERRMX P)
x =
do not careTable 4-12. Status Line Assertion For Diagnostic Command Wrap
Mode
INCOMING MAPPED TO COMMAND LINES ERRMX LINES
CMOO 7
CMOl 6
CMD2 5
CM03 4
DSO 3
DS1 2
SLXO 1
SLXl 0
SLX2 P
484.4.3 DMS/WRT (SLX 2, 1,