SYSTEM   OVERVIEW

11/60

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A year ago I found a PDP-11/60 in the corporate cabinet, but I did not have the means to transport it to my house. The only thing that I took was the console, to prevent cosmetic damage to it. I decided that I would take the system during the visit the next time (May, 2005).

However, due to available room restrictions, I was sure that I could never put the complete corporate cabinet, as shown on the cover of the processor handbook, at my place. So I decided to go for the CPU box and its power supply, the wiring harnesses, the power controller and all loose bits in the cabinet. I already had the console and the console static protection/connection board, and planned to build the PDP-11/60 in a tall H960 cabinet.

DIGITAL introduced the PDP-11/60 in March 1977.
The PDP-11/60 has some attributes that makes the machine interesting. The 11/60 has an option called WCS (Writable Control Store) that allows a user to write his own micro-code and let the processor execute the new instruction(s) at full speed! There are 3 different WCS options:

• M7870      = WCS - Writable Control Store (KU-116)
• M7871      = DCS - Diagnostic Control Store
• M7871-YA = ECS - Extended Control Store

The only other PDP-11 that has a WCS option (KUV11, M8018) is the PDP-11/03, KD11-F processor.
Ritchie Lary wrote the micro-code for the PDP-11/60 to emulate the PDP-8 instruction set, making it the "fastest PDP-8 ever".
It is a pity that the source code seems to be lost. Even Ritchie Lary, the author, no longer had the source when Eric Smith inquired some years back (~2011 - 2012), and Ritchie did not think that anyone else was likely to have it. So, it appears to be lost forever.
Update from Paul Koning (Feb. 2018)
A few more snippets of information: it was used by the WPS-8 development group in Merrimack, NH (a few cubes over from my first office at DEC). The host ran RSTS/E, and there was a RSTS "Runtime System" as part of the machinery.
I've never seen any of the code; the brief description above is all I know.

Jumps within this page are the following.

• General system information
• PDP-11/60 console description
• This PDP-11/60 system configuration

The PDP-11/60 is a somewhat rare machine, as it was not one of the more popular models. Arguably, the processor should have been designed with the PDP-11/45-55-70 style 22-bit memory management, not the PDP-11/40-34 style (18-bit).
Perhaps the non-popularity of the PDP-11/60 caused the machine to have a short life span during which it was shipped (only from 1977 to 1981 or so).
However, the Floating Point (option FP11-E) is pretty good, and of course the PDP-11/60 was user micro-programmable.
The system was available in 4 different configurations. Three configurations were housed in a Low Boy Corporate cabinet.
The main difference between these three was the installed mass storage option in the top left and right side. The choice available was either two RK06 removable pack disk drives, or a combination of a RK05f fixed and RK05j removable pack disk drive, or no mass storage peripherals at all, just two blank panels. The fourth configuration is housed in a High Boy Corporate cabinet and does not have any peripherals in the cabinet.
Here you see my Low Boy cabinet system in its original state. The expansion card cage is already outside the cabinet.
The two upper bays contained a PC05 paper tape reader/punch at the left side and an RX01 floppy drive unit at the right side.

more to be added ...

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The system console is in the middle at the front side of the corporate cabinet between the two bays, but my H960 rack-mount (home-brew) version the console is installed on a blank panel. See the page "11/60 in H960 rack".
If you have other ideas for the installation of the system console in an H960 rack configuration, let me know!

The 11/60 console (KY11-P) resembles the PDP-11/34A "full" console: it has the calculator-style keypad and the six 7-segment red LED displays. A key switch is used to turn on/off and control the system.

PDP-11/60 programmer's console switches
5-position  key switch	STD BY DC OFF removes DC power from the processor and core memory. MOS memory battery charger remains on. POWER Applies power to all units. All console controls are operable in Console mode. LOCK Deactivate all keypad functions. With the key switch in LOCK position, the position of the slide switch has no effect when power-up occurs. R1 Remote 1. Local control is deactivated to allow operation from a remote console. The octal display on the console is blanked. R2 Remote 2. Console action is the same as R1.
3-position  slide switch	If the key switch is in the LOCK position (blocking all keypad functions) inadvertent operation of the slide switch has no effect. On power-up, the slide switch is treated as if it is in the RUN position. If the battery is depleted (in MOS memory systems), RUN is altered to a BOOT action. If the key switch is not in the LOCK position, and a power-fail occurs, 3 choices of recovery are available : BOOT Power-up to the M9301 bootstrap terminator. RUN Power-up to location 24 which contains the power-up vector. This action occurs independent of battery status in a MOS memory system. HALT Power-up to the console. The CONSOLE light is turned on and the console keypad buttons are active.

PDP-11/60 programmer's console indicators
six 7-segment displays	The octal display is a six digit, 7-segment display, used to display address or data information. The display allows 18-bits (octal coded) to be displayed. For (L)ADRS, (D)ADRS and HALT/SI functions, decimal points are displayed in conjunction with the octal address. For all other functions, the information is displayed without the decimal points.
RUN	ON  - The processor is executing instructions. OFF - The light goes OFF during an extended wait instruction.
PROC	ON - The processor is the master device and has control of the UNIBUS.
USER	ON - The processor is in User Mode, and certain restrictions on instruction operation           and Processor Status Word loading exist.
CONSOLE	ON - The processor is in Console Mode and is under control of the keypad buttons           (manual operation).
BATT	ON                   - Battery is present and charged. slow blinking - Indicates battery is charging. fast blinking  - Indicates loss of power,                            battery is discharging while maintaining MOS memory contents. OFF                 - No battery present or battery depletion if battery is present.

The following table gives an overview of the buttons of the keypad. The CNTRL (Control) button is used in conjunction with other buttons to prevent accidental operation of certain functions. When used, the CNTRL button must be depressed first and held down while the other button is pressed, just as the operator keypad of the PDP-11/34A.
Those buttons that are interlocked with the CNTRL button are indicated with an asterisk (*) in the table below.

PDP-11/60 programmer's console keypad
0,1,2,3,4,5,6,7	Allows the operator to enter octal data into the display. The numeric buttons work in Console Mode and in Run Mode.
HALT / SI	Halt / Single Instruction - Depressing this button while the processor is in Run Mode will halt the processor between instructions, after outstanding trap sequences and before bus requests. The processor is now in Console Mode and the CONSOLE indicator is turned on. The octal display indicates the program counter for both HALT and SI functions. Depressing the HALT/SI button now causes a single instruction to be executed. To initialize the system without a program start, it is necessary to depress the HALT/SI button while holding the START button down.
D(SWR) *L(SWR)	Display Load Switch Register , Load Switch Register Display the contents of the Console Switch Register in both Console and Run Mode. If this button is depressed while the CNTRL button is held, the contents of the Temporary Switch Register are loaded into the Console Switch Register. The contents of the Console Switch Register are displayed. Operative in both Console and Run Modes.
(D)ADRS	Displays the contents of the Console Address Register and clears the DISPLAY LOCK bit, thus enabling the program movements to address 777570. Operation occurs in both Console and Run Modes.
Buttons only active in Console Mode
(L)ADRS	Load Address - Depressing this button transfers the contents of the Temporary Switch Register to the Console Address Register to be used in subsequent DEP or EXAM operations. The contents of the Console Address Register is displayed in the octal display and all the decimal points are turned on.
EXAM	Examine - Depressing this button accesses the UNIBUS address specified in the Console Address Register and displays the contents of that address in the octal display. Sequential examines increment the address by two and display the contents of the incremented addresses. This incrementation process is stopped if any other button except numerics is pressed.
DEP	Deposit - Depressing this button deposits the contents of the Temporary Switch Register at the UNIBUS address specified by the Console Address Register. The Console Switch Register is not changed. To deposit data in sequential addresses, all that is necessary is to press the DEP button. This automatically word-increments the Console Address Register and deposits the data into the incremented address. This process is stopped if any other button except numerics is depressed.
*CONT	Continue - Depressing this button allows the processor to leave the Console Mode and continue operation at the present Program Counter location without a BUS INIT. The display is unaltered.
*START	Start - Depressing this button begins machine operation at the address (PC) specified by the Console Address Register after a BUS INIT signal. Operation occurs only in Console Mode and the CONSOLE light is turned off. The display is unaltered.
*BOOT	Bootstrap - Depressing this button will cause a BUS INIT and will start the boot program of the M9301 module. The display is unaltered.
*DIAG	Diagnostic - Depressing this button transfers control to the DCS (Diagnostic Control Store) module, if present. Otherwise, the computer enters Console Mode. The display is unaltered.
*MAINT	Maintenance - This button is used to read and write the internal registers. The procedure for reading an internal register is the following. Load the Temporary Switch Register with the read opcode of the register that you want to read. Depress the (L)SWR button while holding the CNTRL button depressed. This transfers the contents of the Temporary Switch Register to the Console Switch Register. Depress the MAINT button while holding the CNTRL button depressed. The console display will display the contents of the register specified in the first step. The procedure for writing an internal register is the following. Load the Temporary Switch Register with the write opcode of the register that you want to write. Depress the (L)SWR button while holding the CNTRL button depressed. This transfers the contents of the Temporary Switch Register to the Console Switch Register. Load the Temporary Switch Register with the data to be written by depressing the applicable numeric buttons. Depress the MAINT button while holding the CNTRL button depressed. The console display will display the data that has been written into the specified register.

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As usual, slot #1 is at the right hand side when you stand in front of the computer. So, from right to left you see the following system units in my PDP-11/60 processor box. PDP-11/60 backplane KD11-K processor boards M7870 - KU116 WCS (still empty ...) M7872 - KD11-K micro word module M7873 - KD11-K decode module M7874 - KD11-K data paths module M7875 - KD11-K cache memory and MMU M7876 - KD11-K timing module M7877 - KD11-K status module M7878 - FP11-E FNUA (Next micro Address) M7879 - FP11-E FLTEXP (Exponent) M7880 - FP11-E MULNET (Multiplying Network) M7881 - FP11-E FALU (Arithmetic Logic Unit) M7856 - DL11-W serial I/O port M7856 - DL11-W serial I/O port M7856 - DL11-W serial I/O port, system console DD11-KF 9-slot 11/60 MOS memory backplane DD11-CK 4-slot UNIBUS expansion backplane