OPERATING CONTROLS AND INDICATORS The front panel of the 2100A Computer is available in two con- figurations: an operator panel (standard) and a controller panel (optional). The operator panel provides display and control of the working registers, phase status and fault indicators, and operating controls. The controller panel may be used in applications where an operator panel is seldom required. The panels are easily interchangeable so that, if desired, installations having more than one 2100A Com- puter may share an operator panel among several units. This section describes the functions of the controls and indicators on both versions of the panel, plus basic operating procedures. 5.1 OPERATOR PANEL Figure 5.1 illustrates the operator panel and briefly describes the function of each control and indicator. The following paragraphs provide additional explanatory information. Functions are grouped according to the type of operation. 5.1.1 16-BIT DISPLAY REGISTERS The DISPLAY REGISTER displays the contents of any one of the six 16-bit working registers when in the halt mode. (Only the S-register is displayed in the run mode.) An illuminated bit push- button is a "1"; a non-illuminated bit pushbutton is a "0". The bit content changes state each time the pushbutton is pressed, and the entire display may be cleared by pressing CLEAR DISPLAY. When power is initially turned on, the S-register is automatically selected. Thereafter, while in halt mode, any of the six registers may be selected by pressing the appropriate select switch: A, B, P, M, S, or MEMORY DATA. The register currently selected for display is indicated by lighting of the pushbuttons. After a programmed or manual halt, MEMORY DATA is auto- matically selected. This causes the contents of the last accessed memory cell to be displayed -- which will be the halt instruction code in the case of programmed halts. As long as a register is being displayed, the original contents of that register may be redisplayed, if altered by pressing DISPLAY REGISTER pushbuttons, simply by pressing the same select push- button again (A, B, P, M, S or MEMORY DATA). However, when any other select pushbutton is pressed (or if the computer is run or stepped) the last indicated display becomes the new contents for that reister, and the old contents is lost. 5-1 -------------------------------------------------------------------------- ______ | (hp) | 2100 COMPUTER |______| HEWLETT PACKARD -------------------------------------------------------------------------- DISPLAY REGISTER 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ | | | || || | | || || | | || || | | || || | | || || | |__| |__||__||__| |__||__||__| |__||__||__| |__||__||__| |__||__||__| LOADER INT. EXT. EXE- MEMORY ENABLE PRE. PRE. FETCH IND CUTE PARITY A B M DATA __ __ __ __ __ __ __ __ __ __ __ | | | | | | | || || | | | | | | | | | | | |__| |__| |__| |__||__||__| |__| |__| |__| |__| |__| HALT INSTR INT. EXT- CLEAR DEC INC RUN CYCLE STEP SYS. END OVF DISPLAY S P M M __ __ __ __ __ __ __ __ __ __ __ | | | | | | | || || | | | | | | | | | | | |__| |__| |__| |__||__||__| |__| |__| |__| |__| |__| -------------------------------------------------------------------------- -------------------- | POWER ON | | ___ | | POWER / \ LOCK | | OFF \___/ ON | | | -------------------- --------------------------------------------------------------------------- Figure 5.1. Operator Panel Controls and Indicators (Part 1) 5-2 16-BIT REGISTERS DISPLAY REGISTER. Bit light on = 1, off = 0. Press switch to com- plement any bit. MEMORY DATA. Press to display contents of location referenced by M. Lit when selected. Can press again to redisplay unmodified contents. Selected when computer is halted. INCREMENT M. Press to increment M. If memory data selected, display is updated. M. Press to display M-register. Can also press again to redisplay unmodified contents. P. Press to display P-register and set Fetch phase. Can press again to redis- play unmodified contents. B. Press to display B-register. Can press again to redisplay unmodified contents. A. Press to display A-register. Can press again to redisplay unmodified contents. S. Press to display S-register. Can press again to redisplay unmodified con- tents. Automatically selcted in run mode. CLEAR DISPLAY. Press to clear display register. 1-BIT REGISTERS OVF. Overflow register. Light on = 1, off = 0. Press to complement. EXTEND. Extend register. Light on = 1, off = 0. Press to complement. OPERATING CONTROLS INTERRUPT SYSTEM. Light on indicates interrupt system enabled. Press to complement. INSTR STEP. Press to execute single instruction. EXTERNAL PRESET. Press to clear I/O channels. INTERNAL PRESET. Set Fetch phase, clear parity error indication and overflow, disable interrupt system and memory protect. HALT/CYCLE. Halt the computer or perform one instruction phase. LOADER ENABLE. Press to enable/disable loader. RUN. Start execution, disable panel. POWER OFF/POWER ON/LOCK ON. Key-operated power switch. Panel disabled in LOCK ON position. PHASE STATUS INDICATORS FETCH. Indicates Fetch phase is next. IND. Indicates Indirect phase is next. EXECUTE. Indicates Execute phase is next. FAULT INDICATORS PARITY. Light on indicates that a memory parity error has occurred (If P.E. HALT mode selected). EXTERNAL PRESET. Light on indicates a power failure occured (if lo- cation 04 contains HLT). 5-3 Note that pressing the M pushbutton displays the address of a memory location, and pressing MEMORY DATA displays the con- tents of that location. Depending on which of these is selected, consecutive addresses or consecutive contents for adjacent memory calls (either higher or lower) may be displayed by repetitively pressing INCREMENT M or DECREMENT M. These two push- buttons are only momentarily illuminated when pressed. Pressing the P pushbutton also sets the fetch phase, so that execution may begin (at the location indicated by the P-register) simply by press- ing RUN. 5.1.2 FAULT INDICATORS Provision is made to indicate two possible hardware faults. One is a parity error as a result of reading from memory. If the PARITY light is on, a parity error has occured. In the halt mode, the light may be turned off by pressing INTERNAL PRESET. In the run mode, the light is turned off by a parity error interrupt, and thus is not ordinarily on long enough to be visible. The other indicated hardware fault is power failure. If the ARS/ ARS switch is set to ARS (auto-restart) and location 04 contains a HLT instruction, the EXTERNAL PRESET pushbutton will light on restoration of power, and the machine will halt. The light is turned off by pressing the EXTERNAL PRESET pushbutton. (In a restart routine the light would be turned off by the CLC 04 instruction.) 5.1.3 PHASE STATUS INDICATORS There are three indicators which signal the state of the computer: FETCH, IND (for indirect), and EXECUTE. The next phase to occur if the computer is run or stepped is the phase indicated by the lighted status indicator. Thus if the FETCH light is on, the computer will fetch an instruction from the address currently pointed to by the P-register when the computer is run or stepped. (It should be noted that indirect references for the extended arith- metic instrucions are obtained in an Execute phase, not an Indirect phase.) The indicators are also operative in the run mode. 5-4 5.1.4 1-BIT REGISTERS The contents of the Extend and Overflow registers are continu- ously displayed by the EXTEND and OVF pushbutton lights (in both halt and run modes). If the pushbutton light is on, the regis- ter contents is a "1"; if not on, the register contents is a "0". In the halt mode, the content changes state each time the pushbutton is pressed. 5.1.5 OPERATING CONTROLS The eight pushbuttons grouped together as operating controls gen- erally control start/stop and other related functions. Since the effects of each pushbutton differ one from another, they are dis- cussed separately below. INTERRUPT SYSTEM. This pushbutton indicates and controls the state of the interrupt system. When the pushbutton light is on, the interrupt system is enabled (flag set). When the light is off, the interrupt system is disabled (flag clear). Each time the pushbutton is pressed, while the cmputer is halted, the flag changes state. INSTR STEP. This pushbutton is used to advance program execu- tion by instruction. The program advances one instruction each time thepushbutton is pressed. If the RUN light stays on, an in- finite indirect loop is indicated; press HALT to terminate the loop. EXTERNAL PRESET. This pushbutton disables the input/output channels. From I/O address 06 and up, all Control flip-flops are cleared and flag flip-flops are set. If the EXTERNAL PRESET pushbutton lights, a power failure has occurred (see description under Fault indicators). INTERNAL PRESET. This pushbutton presets the computer to the fetch phase, clears the PARITY indicator, clears overflow, and disables both the interrupt system and the memory protect logic. HALT/CYCLE. In the run mode, this pushbutton is used to halt the computer at the end of the current phase. The pushbutton 5-5 lights when the computer halts, and all other panel controls be- come enabled. In the halt mode, the pushbutton may be used to advance program execution by phase. One phase occurs (and the light goes off momentarily) each time the pushbutton is pressed. LOADER ENABLE. This pushbutton enables access to the basic binary loader (last 64 locations of memory) for the purpose of loading binary programs. When the push button is pressed the light goes on, and stays on as long as the loader is enabled. After a programmed or manual halt, the light goes off and the loader is again disabled. (The loader can also be disabled by press- ing the pushbutton again.) RUN. Pressing RUN starts the computer in the current state. The RUN pushbutton light is on while the computer is in the run mode, and all panel controls are disabled except HALT/CYCLE, DISPLAY REGISTER, and CLEAR DISPLAY. Pressing RUN automatically causes the S-register contents to be displayed, and no other register may be selected while the computer is in the run mode. Thus, to the operator, the DISPLAY REGISTER effectively becomes the S-register. This register may be addressed as select code 01 by programmed instructions, and may be manually altered by the operator. POWER OFF/POWER ON/LOCK ON. This is a three-position, key- operated switch controlling primary power to the computer. The key is removable only in the horizontal POWER OFF and LOCK ON positions. In the LOCK ON position the panel controls are enabled and the key may not be removed. If it is desired to inhibit the operation of the automatic restart logic when turning power on, the EXTERNAL PRESET pushbut- ton may be held depressed while turning the power switch. 5.2 CONTROLLER PANEL Figure 5.2 illustrates the optional controller panel and briefly des- cribes the function of each control and indicator. The following paragraphs provide additional explanatory information. 5-6 -------------------------------------------------------------------------- LOAD PRESET RUN HALT PARITY __ __ __ __ __ | | | | | | | | | | |__| |__| |__| |__| |__| -------------------------------------------------------------------------- -------------------- | POWER ON | | ___ | | POWER / \ LOCK | | OFF \___/ ON | | | -------------------- --------------------------------------------------------------------------- OPERATING CONTROLS LOAD. After preset, press to load program. Light on during load. PRESET. Press to set Fetch phase, turn off I/O channels, interrupt sys- tem, memory protect, and indications for parity error and power fail. RUN. Press to start program execution. Light on in run mode. HALT. Press to halt execution at end of current phase. Light on when halted. POWER OFF/POWER ON/LOCK ON. Key-operated power switch. Panel disabled in LOCK ON position. FAULT INDICATORS PRESET. Light on indicates power failure occured. (Refer to text.) PARITY. Light on indicates a memory parity error has occured, with P.E. INT/HALT switch set to HALT. Figure 5.2. Controller Panel Controls and Indicators 5-7 PARITY. If the PARITY light is on, a parity error has occurred as a result of reading form memory. In the halt mode, the light may be turned off by pressing the PRESET pushbutton. In the run mode, the light is turned off by a parity error interrupt. RUN. Pressing RUN start the computer in the current state. The RUN pushbutton light is on while the computer is in the run mode, and the PRESET pushbutton is disabled. HALT. This pushbutton is used to halt the computer at the end of the current phase. The pushbutton lights when the computer halts, and the PRESET pushbutton becomes enabled. PRESET. This pushbutton disables the input/output channels clears the Control flip-flops and sets flag flip-flops from I/O address 06 and up) turns off the interrupt system, clears the Overflow, A-, B-, and P-registers, clears the PARITY indicator, disables the memory protect logic, and presets the computer to the fetch phase. Pressint the PRESET pushbutton also clears a power failure indi- cation (PRESET pushbutton light on) if power has failed and is restored. Note that PRESET will light only if the internal ARS/ ARS switch is set to ARS and location 04 contains a HLT instruction. If the RUN pushbutton is pressed after PRESET, the computer will begin program execution from location 0 (P-register = 0). The first two instructions executed will be NOP's (A- and B-registers = 0), and the computer will then begin executing at location 00002. This provides a convenient cold-start linkage in the absence of an operator panel. LOAD. This pushbutton is used to load a program from a tape reader or disc. In the halt mode, pressing the LOAD pushbutton causes the loader starting address to be loaded into the P-register, enables the loader locations, and starts the run mode. The push- button light remains on until a programmed or manual halt occurs. The halt disables the loader and turns off the light. POWER OFF/POWER ON/ LOCK ON. The power control switch is not replaced when panels are interchanged. Refer to the des- cription given previously. 5-8 5.3 INTERNAL SWITCHES Although most of the internal switches are intended for checkout or maintenance purposes, two of these are of interest to the user. The following paragraphs describe the functions of these switches. Access to the switches is obtained by removing the computer top cover; each switch is mounted near the top edge of a printed-circuit card, the location of which is specified in the following text. ___ ARS/ARS ___ The ARS/ARS switch is used to specify the action which the computer should take on recovery from a power failure. With the switch in the ARS position, the computer will interrupt to location 00004 when power returns to normal operating levels; this permits entry to a restart program. With the switch in the ARS position, the computer will halt on recovery of power. The ARS/ARS switch is located on the I/O control card in slot 7. INT/HALT The P.E. INT/HALT switch is used to specify the action which the computer should take on detection of a memory parity error. With the switch in the INT position, the computer will interrupt to location 00005 for entry to a parity error subroutine. With the switch in the HALT position, the computer will halt. The P.E. INT/HALT switch is located on the I/O buffer card in slot 8. 5.4 PANEL OPERATION The following procedures describe, in general, the basic load and run operations for the 2100A Computer. Depending on whether or not a disc is present in the system, loading is accomplished by means of the basic binary loader (BBL) or basic binary disc loader (BBDL). All procedures require that the power-switch key be in the vertical POWER ON position (panel enables). 5.4.1 LOADING WITH THE BASIC BINARY LOADER It is assumed that the basic binary loader program is present in memory, and is properly configured for the channel number of 5-9 the input device and for the size of memory. Refer to the soft- ware operating manual for the procedure required to configure the loader. Loading is accomplished as follows: a. Turn on the input device and prepare for reading (e.g. load tape in tape reader). The input program must be in binary form, containing absolute addresses. b. Press S to select the S-register. This will cause the S- register contents to be displayed in the DISPLAY REGISTER. c. Clear bits 0 and 15 of the display. (These bits are to be set only for certain nonloading check operations; refer to soft- ware operating manual.) The status of the remaining bits is not significant. d. Press P to select the P-register. This will cause the P- register contents to be displayed in the DISPLAY REGISTER. e. Set the display to the starting address of the basic binary loader, according to table 5-1. f. Press EXTERNAL PRESET and INTERNAL PRESET. This initializes the external hardware (I/O channels) and the inter- nal hardware (central processor). g. Press LOADER ENABLE, and then press RUN. The lights for both switches will remain on while the input operation is in progress. h. When the input device stops, the HALT light will go on, RUN and LOADER ENABLE lights will go off, and the DISPLAY REGISTER should indicate 102077 (octal), with MEMORY DATA automatically selected. The load is complete. If the halt code is not 102077 when the device stops, these has been an error in the loading process. Two possible error condi- tions are indicated by the loader, which changes the halt code to identify the type of error. A halt code of 102055 indicates an address error; check if the proper tape is being read, or if it is in 5-10 backwards. A halt code of 102011 indicates a checksum error; check for possible bad tape, or dirty tape reader or tape. MEMORY STARTING ADDRESS OF LOADER SIZE For Paper Tape For Disc 4K 07700 8K 17700 17760 12K 27700 27760 16K 37700 37760 24K 57700 57760 32K 77700 77760 Table 5.1. Loader Starting Addresses 5-11 5.4.2 LOADING WITH DISC LOADER If a disc is present in the system, the basic binary disc loader (rather than the basic binary loader) occupies the protected loader locations. This loader allows loading from either disc or paper tape. The choice is made by selected one of two possible starting addresses, as indicated in table 5.1. For paper tapes the procedure is the same as described above for the basic binary loader; steps "b" and "c" can be omitted. The following procedures for disc loading asssume that the basic binary disc loader is present in memory, and is properly configured for the I/O channel numbers being used and for the size of memory. The input program on disc must be in binary form, containing absolute addresses. a. Press P to select the P-register. This will cause the P- register contents to be displayed in the DISPLAY REGISTER. b. Set the display to the starting address in the loader which is appropriate to the input source (disc) and memory size, as indicated in table 5.1. c. Press EXTERNAL PRESET and INTERNAL PRESET. This initializes the external hardware (I/O channels) and the internal hardware (central processor). d. Press LOADER ENABLE, and then press RUN. In the case of disc loading, the load may occur too quickly to detect visually from the panel lights. However, a correct load is indicated (for either tape or disc) by a display of 102077 (octal), with MEMORY DATA automatically selected. (The P-register con- tents could also be checked. With tape loading, the address should have changed from the first to the last address, plus one, of the loader. With disc loading, the P-register should contain octal 10.) If the displayed halt code is not 102077 when the load is complete, there has been an error. FOr disc loading, the error indications are undefinable. For paper tape loading, the loader will alter the halt code to identify the type of error, as described above for basic binary loader operation. 5-12 5.4.3 MANUAL LOADING Short programs may also be loaded manually from the front panel. a. Press M to select the M-register. This will cause the M- register contents to be displayed in the DISPLAY REGISTER. b. Set the display to indicate the desired starting address for the program. c. Press MEMORY DATA. This will cause the current contents of the memory location to be displayed in the DISPLAY REGISTER. d. Change the displayed contents to the binary instruction code for the first instruction of the program to be loaded. (It may be faster to press CLEAR DISPLAY and begin coding from an all-zero display.) e. Press INCREMENT M. The contents of the next memory location will be displayed, and the M-register, although not displayed, will be incremented. f. Enter the next instruction into the DISPLAY REGISTER. g. Repeat steps "e" and "f" until the entire program has been loaded. To check which location is being displayed, M can be pressed at any time in the procedure to display the current address. 5.4.4 RUNNING PROGRAMS To run a program after it has been loaded: a. Press P to select the P-register. b. Set the display to the starting address of the program. 5-13 c. Press EXTERNAL PRESET and INTERNAL PRESET. d. Press RUN. The RUN light will be on as long as the program is running. All panel controls except HALT/CYCLE, DISPLAY REGISTER, and CLEAR DISPLAY are disabled. The S-register is automatically selected, and may be manually changed via the DISPLAY REGISTER. 5.5 OPERATING PROCEDURES FOR CONTROLLER PANEL 5.5.1 LOADING PROGRAMS It is assumed that the loader program is present in memory, and that the loader and the panel are properly configured from the type of loader (paper tape or disc0, the channel number of the input device, and the applicable memory.size. Refer to the 2100A Installation and Maintenance manual for the pcoredure required to configure the panel, and to the software operating manual for the procedure required to configure the loader. Loading is accomplished as follows: a. Turn on the input device and prepare for reading (e.g., load tape in tape reader). The input program must be in binary form, containing absolute addresses. b. Press PRESET. This initializes both the external hard- ware (I/O channels) and the internal hardware (central processor). c. Press LOAD. The LOAD light will be on and will remain on during the load (or until the pushbutton is released in the case of disc loading). No error checking is provided. 5-14 5.5.2 RUNNING PROGRAMS To run the loaded program, press PRESET and then press RUN. The PRESET switch causes the A-, B-, and P-registers to be cleared, thus causing execution to begin at location 00000 (A-register). The computer executes the NOP instruction contained in the A- register (all-zero word), and also the NOP in the B-register. Then in location 00002, a JMP instruction causes a jump to the starting instruction of the program. The RUN light will be on as long as the program is running. Only the HALT switch is enabled. However, even this switch may be disabled by turning the power-switch key to the horizontal LOCK ON position. The key may be removed in this position, and thus protect the state of the computer from accidental tampering. 5-15