TM11 magtape controller

The TM11, TMA11 and TMB11 magnetic tape controllers are a series of UNIBUS device controllers, used with a number of different 1/2" magnetic tape drives from DEC. They are all compatible, both in their interface to the drives, and in their programming interface.

The TM11 and TMA11 are almost identical in construction; they are implemented as a series of smaller standard FLIP CHIPs in a custom-wired 19" backplane.

M7911 card from a TMB11

The TMB11 is a re-implementation, using two larger custom boards - one hex (M7912) and one quad (M7911) - along with 4 generic (i.e. not device-unique) UNIBUS-specific FLIP CHIPs (M105, M795, M796, M7821); all of which plug into a custom hex-high four-slot system unit backplane (for a BA11, etc box).

Configurations

The TM11 series controllers connect to a 'Master drive', which includes considerable extra electronics; additional 'Slave' drives may be connected to the Master drive.

Much of the extra functionality is related to the operation of the drive (CRC, etc); however, the TM11 series controllers generate a Positive bus, which a Master drive (depending on the drive type in use) converts to a Negative bus for the Slave drives - Slave drives of some types have a Negative bus only.

The TM11 series controllers were initially used with the TU10 magtape drives, for which the slaves are all Negative bus. Later, they were used with the TS03 drive (for which the Master drive includes an M8920 board, to interface to a TM11). They were also used with the TU10W drive (which is the later TU16 drive, without the TM02 controller); and the TE16 drive, when it is upgraded to TE10W (Positive bus - Master and Slave) or TE10N (Negative bus - Slave).

Device registers

Register	Abbreviation	Address
Status Register	MTS	772520
Command Register	MTC	772522
Byte Record Counter	MTBRC	772524
Current Memory Address Register	MTCMA	772526
Data Buffer	MTD	772530
TU10 Read Lines	MTRD	772532

772520: Status Register (MTS)

Illegal Command	EOF	CRE	PAE	BGL	EOT	RLE	BTE	NXM	SELR	BOT	7CH	SDWN	WRL	RWS	TUR
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

772522: Command Register (MTC)

ERR	DEN8-5		PCLR	PEVN	Unit Select			CUR	INT ENB	Extended Memory		Function			GO
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

772524: Byte Record Counter (MTBRC)

BC15 <---> BC00
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

772526: Current Memory Address Register (MTCMA)

MA15 <---> MA00
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

772530: Data Buffer (MTD)

Data (read-only)								Data (read/write)
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

772532: TU10 Read Lines (MTRD)

Timer	CRC/LPCC selector	BTE error	Gap shutdown	Unused			Parity	Data
15	14	13	12	11	10	09	08	07	06	05	04	03	02	01	00

Drive bus

The connection to the master drive is a standard dual-width BC11-A cable, as used for the UNIBUS. This is the pinout for the TM11 (the other two are basically identical to this):

Pin	Signal Name	Use	Source	Pin	Signal Name	Use	Source
AA1	SEL0	Tape unit select	Controller	AA2
AB1	SEL1			AB2	Ground
AC1	SEL2			AC2
AD1				AD2	WD0	Write Data	Controller
AE1	DEN0	Density (see table below)	Controller	AE2	WD1
AF1	DEN1			AF2	WD2
AH1				AH2	WD3
AJ1	WXG	Write Extended Gap	Controller	AJ2	WD4
AK1	FWD	Tape Forward		AK2	WD5
AL1	RWD	Tape Rewind		AL2	WD6
AM1	WRE	Write Enable		AM2	WD7
AN1	Ground			AN2	REV	Tape reverse	Controller
AP1				AP2	CINIT	Initialize
AR1				AR2	SET	Required to start any tape operation
AS1				AS2	WDR	Write Data Ready
AT1				AT2	PEVN	Even Parity
AU1				AU2	WFMK	Write File Mark
AV1				AV2	Ground
BA1	RDS	Read Strobe	Drive	BA2
BB1	SDWN	Tape Settle Down		BB2	Ground
BC1	TUR	Tape Unit Ready		BC2
BD1	Ground			BD2	WRS	Write Strobe	Drive
BE1				BE2	CRCS	CRC Strobe
BF1	RD0	Read Data	Drive	BF2	RWS	Rewind Status
BH1	RD1			BH2
BJ1	RD2			BJ2
BK1	RD3			BK2	BOT	Beginning of Tape	Drive
BL1	RD4			BL2	WRL	Write Lock
BM1	RD5			BM2	VPE	Vertical Parity Error
BN1	RD6			BN2	SELR	Select Remote
BP1	RD7			BP2	7CH	7-Track Unit
BR1	RDP	Read Parity Bit	Drive	BR2	EOT	End of Tape
BS1	FMK	File Mark Read		BS2	CRCE	CRC Error
BT1	Ground			BT2	LRCE	Longitudinal Parity Error
BU1				BU2	LRCS	Longitudinal Parity Strobe
BV1	MAN CLR L			BV2	Ground

For the TMA11 and TMB11, delete the "MAN CLR L", and re-name "DEN0" and "DEN1" to "DEN8" and "DEN5" respectively. The encoding of the two density bits is:

DEN 5	DEN 8	Mode
0	0	200 bpi, 7-channel
0	1	800 bpi, 7-channel
1	0	556 bpi, 7-channel
1	1	800 bpi, 9-channel

Module Count Table

The following table gives a listing of the FLIP CHIPs used in the TM11. (Drawn from module count charts, confirmed in module utilization drawings.)

Single height boards:

Type	Count	Function
G736	1	Jumper Module
M105	1	UNIBUS Address Selector
M111	5$	Sixteen Inverters
M112	3	Ten 2-input NOR Gates
M113	7$	Ten 2-input NAND Gates
M115	2	Eight 3-input NAND Gates
M117	1	Six 4-input NAND Gates
M121	2	Six AND/NOR Gates
M127	3	Three 2-2-2-3 AND/NOR Gate
M149	4	Nine 2-input NAND Wired OR Matrix
M163	1	Dual Binary-to-Octal Decoder
M203	1	Eight S/R Flip-Flops
M205	2	Five D Flip-Flops
M216	5	Six D Flip-Flops
M239	1	Three 4-bit Counter Registers
M304	2	Four One-Shot Delays
M307	1	Two Integrating One-Shot
M627	3	Six NAND Power Amplifiers
M688	1	UNIBUS Power Fail Driver
M7821	1	UNIBUS Interrupt Control
M784	1	UNIBUS Receiver
M785	1	UNIBUS Transceiver
M796	1	UNIBUS Master Control
M797	1	Register Selection
M798	1	UNIBUS Drivers

$ = The module count table in the TM11 manual gives a different number, but that manual seems to be wrong; the prints, and an actual unit, have the number given here.

Double height boards:

• M795 - Word Count and Current Memory Address

The table in the TM11 manual calls for two of these, but this is clearly wrong.

Module Locations

These are the module locations for the TM11:

Slot	Connector A	Connector B
5	M111	M627
6	M111	M901@
7	M798	G736
8	M149	M149
9	M105	M784
10	M7821	M785
11	M796	M797
12	M795
13	M149	M149
14	M216	M205
15	M163	M112
16	M113	M111
17	M115	M121
18	M216	M216
19	M121	M113
20	M117	M627
21	M239	M113
22	M115	M205
23	M111	M127
24	M216	M127
25	M112	M127
26	M112	M111
27	M113	M901@
28	M203	M688
29	M113	M113
30	M304	M627
31	M307	M216
32	M304	M113

@ = Cable

For the TMA11, slot 27B contains an M7854 "OPI/BTE Detector".