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US3838400A Expired / Lapsed US ⏱️ 0.0 years remaining

Maintenance facility for a magnetic tape subsystem

Assignee: Storage Technology Corp
•
Filing: 1973-11-12
•
Granted: 1974-09-24
•
Expires: 1993-11-12
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Abstract

Abstract A control unit for a magnetic tape subsystem of a data processing system includes a maintenance facility. This maintenance facility permits the exercise of the magnetic tape subsystem for diagnostic and maintenance purposes. The control unit is of the microprogram type, in which a control memory contains micro orders which control the operation of the magnetic tape units. The maintenance facility exercises the tape subsystem in two different manners-with the Input/Output command language of the CPU or with the micro order language of the control unit. This can be performed while the magnetic tape subsystem is switched offline to the CPU, or time-multiplexed with the operational usage of the magnetic tape subsyste by the CPU. The control unit includes a random access memory connected in parallel with the control memory. In the diagnostic mode, micro orders are transferred from a magnetic tape unit to the random access memory. Then, sequences of these micro orders are performed in the same way that micro orders stored in the control memory are otherwise executed in order to perform diagnostic testing. The data path transferring the micro orders from the magnetic tape unit to the random access memory is a simple one which bypasses the normal circuits which might otherwise introduce errors into the diagnostic micro orders. Amplitude sensors, which are otherwise used for error detection and correction, are connected to majority circuits which produce outputs when the amplitude sensors indicate that a majority of the data tracks are written with a ''''1.'''' In this manner, very reliable micro orders are obtained for performance of the diagnostic testing function. The maintenance facility provides full micro order control over a Field Engineer Buffer. Data and commands are loaded into a fetched from any buffer position under manual switch control or microprogram control.

Inventors

  • 👤 A Carpentier
  • 👤 J Meadows
  • 👤 L Horsman

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 03:56
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/22; G06F11/2205; G06F11/2221

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 199 words
In a magnetic tape data processing system including a central processor, a plurality of magnetic tape units and a control unit of the type having: a control memory having micro orders stored at addressable locations for controlling the operation of said magnetic tape units, an address register connected to said control memory for addressing said locations, and logic circuitry connected to said control memory for receiving said micro orders, and in response thereto providing control signals to said magnetic tape units, receiving response from said magnetic tape units, and setting said address register to address said memory, said address register, said memory and said logic circuitry being interconnected to send control signals resulting from the decoding and interpretation of micro orders to tape units in response to commands from said central processor, an improved diagnostic facility comprising: a field engineer''s buffer of the read/write random access type, manual control including switches which are set to load commands and data into, or to fetch commands and data from said buffer, and addressing logic connected to said buffer for loading commands and data into, or for fetching commands and data from, said buffer, under control of micro orders from said memory.
Claim 2
Dependent Claim 199 words
In a magnetic tape data processing system including a central processor, a plurality of magnetic tape units and a control unit of the type having: a control memory having micro orders stored at addressable locations for controlling the operation of said magnetic tape units, an address register connected to said control memory for addressing said locations, and logic circuitry connected to said control memory for receiving said micro orders, and in response thereto providing control signals to said magnetic tape units, receiving response from said magnetic tape units, and setting said address register to address said memory, said address register, said memory and said logic circuitry being interconnected to send control signals resulting from the decoding and interpretation of micro orders to tape units in response to commands from said central processor, an improved diagnostic facility comprising: a field engineer''s buffer of the read/write random access type, manual control including switches which are set to load commands and data into, or to fetch commands and data from said buffer, and addressing logic connected to said buffer for loading commands and data into, or for fetching commands and data from, said buffer, under control of micro orders from said memory.
Claim 3
Dependent Claim 39 words
The system recited in claim 1 wherein said addressing logic includes means for sensing special codes in said field engineer''s buffer to cause command fetching to be stopped or continued in a non-sequential manner if tested conditions are present.
Claim 4
Dependent Claim 30 words
The system recited in claim 1 further comprising: manual controls for said field engineer''s buffer for operating said buffer in the performance of functional tests in said magnetic tape subsystem.

References Cited (Backward Citations)

US3659273A Cited
US3603936A Cited
US3696340A Cited
US3703707A Cited
US3798614A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-09-23 1978-03-25 1978-09-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-09-23 1982-03-25 1982-09-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-09-23 1986-03-25 1986-09-24 $7700.00 Window Closed / Lapsed

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