Patent EP0534883A1 successfully refreshed from Google Patents.
EP0534883A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for synchronizing the readout of a sequential media device with a separate clocked device
Assignee: International Business Machines Corp
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Filing: 1992-08-14
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Granted: —
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Expires: 2012-08-14
Abstract
Abstract A method and apparatus for controlling the readout rate of information from a sequential storage medium (104), such as a CD-ROM, to maintain synchronism between the device containing the medium and an independent receiver receiving the information. Information is loaded from the media (104) into a buffer (116) at a rate controlled by pulses from a device clock (124). Information is unloaded from the buffer (116) for utilization by the receiver independently of the loading of the buffer. The amount of free space available in the buffer is measured as information is loaded into the buffer. The rate of the clock (122) is dynamically adjusted in response to the amount of free buffer space to maintain the full state of the buffer within predetermined limits. In this manner, the buffer never empties or fills in response to the unloading by the independent receiver.
Inventors
- 👤 Donald Edward Carmon
- 👤 William George Crouse
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 02:36
CPC Classifications
G; G06; G06F; G06F5/00; G06F5/06; G06F5/10; G06F3/00; G06F3/06; G06F3/0601; G11; G11B; G11B20/00; G11B20/10; G06F2205/00; G06F2205/06; G06F2205/061; G06F3/0628; G06F3/0655; G06F3/0656; G11B20/10527; G11B2020/1062; G11B2020/10814
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
84 words
A method of controlling the readout rate of information from a sequential storage medium, comprising the steps of loading the information from the media into a buffer at a rate controlled by pulses from a clock, unloading information from the buffer for utilization independently of the loading of the buffer, measuring the amount of free space available in the buffer, and adjusting the rate of the clock in response to the measuring step to maintain the amount of free buffer space within predetermined limits.
Claim 2
Dependent Claim
68 words
The method of claim 1 wherein the step of adjusting further comprises suppressing pulses from the clock to slow the rate of loading into the buffer when the buffer is filled to greater than a predefined amount, and inserting clock pulses into the pulse stream from the clock to increase the rate of loading into the buffer when the buffer is filled to less than a predefined amount.
Claim 3
Dependent Claim
35 words
The method of claim 2 wherein the predefined amount is half the capacity of the buffer and the step of measuring further comprises determining if the buffer is less than or greater than half full.
Claim 4
Dependent Claim
66 words
The method of claim 3 wherein the step of determining if the buffer is less than or greater than half full further comprises maintaining write and read addresses for loading and unloading information from the buffer, each time a selected one of the write or read addresses passes the midpoint of the buffer, storing the most significant bit of the other read or write buffer address.
Claim 5
Dependent Claim
73 words
The method of claim 4 wherein the step of adjusting further comprises suppressing a clock pulse each time a write is performed into the buffer in response to the state of the most significant bit indicating a buffer greater than half full, and inserting a clock pulse each time a write is performed into the buffer in response to the state of the most significant bit indicating a buffer less than half full.
Claim 6
Dependent Claim
91 words
Apparatus for controlling the readout rate of information from a sequential storage medium, characterized in that it comprises : a buffer for loading information from the sequential device, a clock for controlling the rate of loading information into the buffer, means for unloading information from the buffer independently of the loading of the buffer, means for measuring the amount of free space available in the buffer, and means responsive to the measuring means for adjusting the rate of the clock to maintain the amount of free buffer space within predetermined limits.
Claim 7
Dependent Claim
82 words
The apparatus of claim 6 wherein the means for adjusting further comprises means responsive to the measuring means for suppressing pulses from the clock to slow the rate of loading into the buffer when the buffer is filled to greater than a predefined amount, and means responsive to the measuring means for inserting clock pulses into the pulse stream from the clock to increase the rate of loading into the buffer when the buffer is filled to less than a predefined amount.
Claim 8
Dependent Claim
24 words
The apparatus of claim 7 wherein the measuring means further comprises means for determining if the buffer is greater or less than half full.
Claim 9
Dependent Claim
117 words
The apparatus of claim 8 wherein the means for determining if the buffer is greater than half full further comprises write and read address registers for loading and unloading information from the buffer, first means activated by a write of information into the buffer for storing the most significant bit of the buffer write address, second means activated by a read of information from the buffer for storing the most significant bit of the buffer read address, third means responsive to the first and second storing means for storing a signal once on each pass, selected from a write or a read pass, through the buffer indicating whether the buffer is greater or less than half full.
References Cited (Backward Citations)
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