Memories of the 4101 - Revision history

Paul at 03:52, 21 November 2011

Paul — Mon, 21 Nov 2011 03:52:57 GMT

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	Contributed by '''Bob Hocking'''		Contributed by '''Bob Hocking'''

Paul at 03:51, 21 November 2011

Paul — Mon, 21 Nov 2011 03:51:57 GMT

←Older revision		Revision as of 03:51, 21 November 2011
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	Contributed by '''Bob Hocking'''		Contributed by '''Bob Hocking'''
		+	<BR><BR>'''Back''' to [[RCA Computer]]

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Paul at 07:28, 10 March 2007

Paul — Sat, 10 Mar 2007 07:28:22 GMT

←Older revision		Revision as of 07:28, 10 March 2007
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	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.		Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.
-	[[Image:Bob loading tape.jpg\|right\|thumbnail\|170px\|Bob loading the Program Recorder: ''Photo – Chris Goodlace'']]	+	[[Image:Bob loading tape.jpg\|right\|thumbnail\|170px\|Bob loading the Program Recorder: <BR>''Photo – Chris Goodlace'']]
-		+
	Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).		Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).

Paul at 07:26, 10 March 2007

Paul — Sat, 10 Mar 2007 07:26:37 GMT

←Older revision		Revision as of 07:26, 10 March 2007
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	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.		Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.
		+	[[Image:Bob loading tape.jpg\|right\|thumbnail\|170px\|Bob loading the Program Recorder: ''Photo – Chris Goodlace'']]

	Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).		Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).

Paul at 07:03, 5 March 2007

Paul — Mon, 05 Mar 2007 07:03:07 GMT

←Older revision		Revision as of 07:03, 5 March 2007
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	Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).		Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).

-	The principal input/output (I/O) device was a Freidan Flexowriter; an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8-bit code. It was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.	+	The principal input/output (I/O) device was a Fridan Flexowriter; an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8-bit code. It was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.

	Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal, for example, due to varying space craft attitude.		Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal, for example, due to varying space craft attitude.

Paul at 09:11, 27 February 2007

Paul — Tue, 27 Feb 2007 09:11:05 GMT

←Older revision		Revision as of 09:11, 27 February 2007
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-	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4K of core memory, later increased to 8K, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2 MHz. The design was very elegant; all logic boards were identical consisted of eight 'nor' gates, as far as I remember.	+	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4K of core memory, later increased to 8K, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2 MHz. The design was very elegant; all logic boards were identical consisting of eight 'nor' gates, as far as I remember.

	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.		Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.

Paul at 09:08, 27 February 2007

Paul — Tue, 27 Feb 2007 09:08:54 GMT

←Older revision		Revision as of 09:08, 27 February 2007
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-	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4k of core memory, later increased to 8k, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2Mhz. The design was very elegant; all logic boards were identical, consisting, as I remember, of eight Nor gates.	+	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4K of core memory, later increased to 8K, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2 MHz. The design was very elegant; all logic boards were identical consisted of eight 'nor' gates, as far as I remember.

-	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below).	+	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below). The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.

-	Data was outputted to the Data Handling system to console displays, a High Speed Modem and a teletype machine.	+	Data was outputted to the Data Handling System to console displays; and to GSFC via a TTY machine (at one line per six seconds) and a High Speed Modem. Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).

-	The software made provision for levelling, orthogonality and droop of the antenna pedestal and for data correction to improve angular data accuracy.	+	The principal input/output (I/O) device was a Freidan Flexowriter; an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8-bit code. It was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.

-	Two 200 Bits Per Inch (BPI) data recorders were provided, one for the real time program and one for recording tracking data for shipment to Goddard Space Flight Centre (GSFC).	+	Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal, for example, due to varying space craft attitude.

-	Tracking data was also outputted to GSFC via a TTY machine at one line per six seconds.	+	In 1970 the data handling system was improved to allow more interrupts and a new version of the computer was installed - the 4101C at a total cost of US$ 258,000.
-		+
-	The principal input/output device was a Friden Flexowriter. This was an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8-bit code. This machine was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.	+
-		+
-	Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal due to, for example, varying space craft attitude.	+
-		+
-	In 1970 the data handling system was improved to allow more interrupts and a new version of the computer was installed - the 4101-C at a total cost of US$ 258,000.	+

	NORAD Elements could now be read into the computer directly from the teletype machine.		NORAD Elements could now be read into the computer directly from the teletype machine.
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	The new 16K core memory became faulty, possibly due to being uncased to make cooling easier, so it acted as an air filter and collected dust. Following unsuccessful attempts by the NASA programmer to reallocate the program to the good bits, the memory unit was hand carried to Hong Kong for repair with its own seat on the aircraft.		The new 16K core memory became faulty, possibly due to being uncased to make cooling easier, so it acted as an air filter and collected dust. Following unsuccessful attempts by the NASA programmer to reallocate the program to the good bits, the memory unit was hand carried to Hong Kong for repair with its own seat on the aircraft.

-	On the return journey, the heavy power supply which was checked in as baggage became lost; I think it turned up the next day. The computer worked fine for a time except that it occasionally stopped when the computer rack was opened. A notice was placed on the rack requesting that it not be opened unnecessarily. However, senior visitors still found it necessary to "Ooh and Ah" at the maze of white wiring and eventually the fault became permanent. After several days the problem was found and fixed by Dave Gardiner. One shielded cable in the middle of several dozen in a tightly laced loom was too short and stressed to the point in a connector where it had fractured. With great difficulty it was re terminated and from then on the computer worked well.	+	On the return journey, the heavy power supply, checked in as baggage, became lost; I think it turned up the next day. The computer worked fine for a time except that it occasionally stopped when the computer rack was opened. A notice was placed on the rack requesting that it not be opened unnecessarily. However, senior visitors still found it necessary to "Ooh and ah" at the maze of white wiring and eventually the fault became permanent. After several days the problem was found and fixed by Dave Gardiner. One shielded cable in the middle of several dozen in a tightly laced loom was too short and stressed at a point in a connector where it eventually fractured. It was re-terminated with great difficulty; from then on the computer worked well.

-	The original CRO 4101 was packed up and shipped to Tananarive (Madagascar) and installed in their "Capri" radar (an FPS-16 with solid state and I.C. electronics). During the installation some logistics support was provided from the CRO Q-6 basement "come in handy cupboard". This was an informal arrangement between Central Stores, a certain Q-6 Senior Tech and the RCA engineer at TAN. A congratulatory TWX was received in due course.	+	The original CRO 4101 was packed up and shipped to Tananarive (Madagascar) and installed in their "Capri" radar (an FPS-16 with solid state and I.C. electronics). During the installation some logistics support was provided from the CRO Q-6 basement "come in handy” cupboard. This was an informal arrangement between Central Stores, a certain Q-6 Senior Tech and the RCA engineer at TAN. A congratulatory TWX was received in due course.

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	'''Back''' to [[RCA Computer]]		'''Back''' to [[RCA Computer]]

Paul at 04:21, 27 February 2007

Paul — Tue, 27 Feb 2007 04:21:37 GMT

←Older revision		Revision as of 04:21, 27 February 2007
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	The original CRO 4101 was packed up and shipped to Tananarive (Madagascar) and installed in their "Capri" radar (an FPS-16 with solid state and I.C. electronics). During the installation some logistics support was provided from the CRO Q-6 basement "come in handy cupboard". This was an informal arrangement between Central Stores, a certain Q-6 Senior Tech and the RCA engineer at TAN. A congratulatory TWX was received in due course.		The original CRO 4101 was packed up and shipped to Tananarive (Madagascar) and installed in their "Capri" radar (an FPS-16 with solid state and I.C. electronics). During the installation some logistics support was provided from the CRO Q-6 basement "come in handy cupboard". This was an informal arrangement between Central Stores, a certain Q-6 Senior Tech and the RCA engineer at TAN. A congratulatory TWX was received in due course.
		+
		+	----
		+	'''Back''' to [[RCA Computer]]

Paul at 04:19, 27 February 2007

Paul — Tue, 27 Feb 2007 04:19:06 GMT

←Older revision		Revision as of 04:19, 27 February 2007
Line 5:		Line 5:
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-	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4k of core memory, later increased to 8k, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2Mhz.The design was very elegant; all logic boards were identical, consisting, as I neither remember, of eight Nor gates.	+	The original RCA 4101 computer was a 30 bit machine with 2 parity bits. It had 4k of core memory, later increased to 8k, possibly prior to installation at CRO. The original clock rate was 1 MHz later increased to 2Mhz. The design was very elegant; all logic boards were identical, consisting, as I remember, of eight Nor gates.

-	Special boards were used for the memory interface and for analog to digital and digital to analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by Slot or Cycle buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below).	+	Special boards were used for the memory interface and for analog-digital and digital-analog conversion. The control panel was vertically mounted and carried rows of gas discharge tubes in diagonal bunches of three displaying the data in all registers in easily read octal format. The computer could be stopped and stepped by 'Slot' or 'Cycle' buttons making fault finding straightforward. Data was entered from a row of octal thumb wheel switches or by paper tape, (see Flexowriter below).

	Data was outputted to the Data Handling system to console displays, a High Speed Modem and a teletype machine.		Data was outputted to the Data Handling system to console displays, a High Speed Modem and a teletype machine.
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	Tracking data was also outputted to GSFC via a TTY machine at one line per six seconds.		Tracking data was also outputted to GSFC via a TTY machine at one line per six seconds.

-	The principal input/output device was a Friden Flexowriter. This was an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8 bit code. This machine was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.	+	The principal input/output device was a Friden Flexowriter. This was an electric typewriter with an eight-hole paper tape punch and reader. It used its own 8-bit code. This machine was an early commercial word processor. A standard letter could be typed, leaving a question mark after for example "Dear". A question mark was eight holes; this stopped the reader, the operator then typed in a person's name. Another key was pressed and the printer continued to type the rest of the letter. The various letters were stored as paper tapes.

	Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal due to, for example, varying space craft attitude.		Pointing data for the radar was supplied by GSFC via a receive-only Teletype machine. The data was in the form of NORAD Elements, a set of parameters which the 4101 program converted into Range, Azimuth and Elevation to point the radar at the satellite. Once the radar had acquired the target, the 4101 generated its own data in the form of an Inter Range Vector (IRV) thus enabling the radar to follow the target in the event of loss of signal due to, for example, varying space craft attitude.

Paul at 03:31, 27 February 2007

Paul — Tue, 27 Feb 2007 03:31:22 GMT

←Older revision		Revision as of 03:31, 27 February 2007
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	<BR>		<BR>
	{{SideMenuQ6}}		{{SideMenuQ6}}
-	Contributed by Bob Hocking	+	Contributed by '''Bob Hocking'''

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