I/O DEVICE ATTACHMENT FOR A COMPUTER

• US 3,805,245 A
• Filed: 04/11/1972
• Issued: 04/16/1974
• Est. Priority Date: 04/11/1972
• Status: Expired due to Term

• Current Assignee: David O. Lewis, Dean O. Zimmerman, Everett G. Brooks, Glenn D. Pooler, Nyles N. Heise
• Original Assignee: David O. Lewis, Dean O. Zimmerman, Everett G. Brooks, Glenn D. Pooler, Nyles N. Heise
• Inventors: Brooks, Everett G., Lewis, David O., Heise, Nyles N., Pooler, Glenn D., Zimmerman, Dean O.
• Primary Examiner(s): Henon, Paul J.
• Assistant Examiner(s): Chapnick, Melvin B.
• Application Number:
  US05/242,962
• Time in Patent Office: 735 Days
• Field of Search: 340/172.5 444/1 235/61.6R,61.9R
• US Class Current: 710/62
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence

Abstract

An attachment for attaching I/O devices to the central processing unit of a computer including a minimized amount of hardware and particularly including registers for holding data that is being transferred from the central processing unit to an I/O device or vice versa. The attachment preferably also includes interrupt control logic for obviating the necessity for continuous polling of the I/O devices. Other necessary control functions for servicing the I/O devices, such as for translating the customer'"'"''"'"'s program I/O commands, initializing interrupt levels, keeping track of the progress of processing by the I/O devices and sensing when an I/O operation is completed are performed by an interpretive mode program contained in a dedicated portion of the memory of the central processing unit.

Claims

1. A calculating system comprising:

a central processing unit, an input-output unit for receiving data from or providing data to said central processing unit and having a data carrying record traveling through the input-output unit, and an attachment connecting said input-output unit with said central processing unit, said central processing unit including an arithmetic and logic unit, a memory and a plurality of temporary storage registers connected with the memory and arithmetic and logic unit so that data in said memory may be processed by the central processing unit in accordance with programs contained in said memory, said input-output unit including an indicator device providing output signals indicative of changing positions of the data carrying record in the input-output unit, said memory including a part having fixed programs therein and said attachment being arranged to cause said fixed programs to be operative under the control of said signals from said indicator device so that the fixed programs cooperate with the rest of the central processing unit to count said signals to thus indicate the position of the data carrying record in said input-output unit.

2. A calculating system as set forth in claim 1 and including another input-output unit for receiving data from or providing data to said central processing unit and having a data carrying record traveling through the unit, said fixed programs being such and cooperating with the rest of said central processing unit in such a manner as to translate an I/O command in another part of said memory and apply it to said fixed programs so as to thereby cause the attachment to distinguish between one of said input-output units and the other of said input-output units.

3. A calculating system as set forth in claim 1, said fixed programs being such as to cooperate with the rest of the central processing unit to make a determination and provide an output signal when said counting has progressed to a pre-determined number of counts.

4. A calculating system as set forth in claim 1, said fixed programs in said memory part being such as to cooperate with the rest of the central processing unit to make a determination and provide an output signal when the counting of said signals by said fixed programs cooperating with the rest of the central processing unit has progressed to a predetermined number of counts and being such as to cooperate with the rest of said central processsing unit so as to indicate the completion of the processing of a data carrying record by said input-output unit when said counting has progressed to said predetermined number of counts.

5. A calculating system as set forth in claim 1, said attachment including means under the control of output signals from said indicator device to make an interrupt of the processing of data by said central processing unit on the reception of one of said output signals.

6. A calculating system as set forth in claim 5, said input-output unit including a reader for reading data from a document card traveling through the reader and said attachment including means for transferring data from the reader to said central processing unit on the existence of said interrupt of the processing of data.

7. A calculating system as set forth in claim 5, said input-output unit including a punching machine for punching a document card traveling through the punching machine, said attachment including means for transferring data from said central processing unit to said punching machine on the existence of said interrupt of the processing of data.

8. A calculating system as set forth in claim 5, said input-output unit including a reader for reading a punched document card traveling through the reader and said attachment including means for transferring data from the reader to said central processing unit on the existence of said interrupt of the processing of data and including a read register for temporarily storing the data read by said reader from a punched document card prior to passage of the information to said central processing unit.

9. A calculating system as set forth in claim 5, said input-output unit including a punching machine for punching data indicating openings in a document card traveling through the machine, and said attachment including means for transferring data from said central processing unit to said punching machine on the existence of said interrupt of the processing of data and including a punch register for temporarily storing data from said central processing unit to be punched by said punching machine into a document card.

10. A calculating system as set forth in claim 5, said input-output unit including a second indicator device providing an output signal when said data carrying record has reached a certain point in traveling through the input-output unit and the attachment including means under control of said last named output signal to thereafter transfer data between said input-output unit and said central processing unit on the existence of said interrupt of the processing of data.