Browse Prior Art Database

Two Way Sequential Transfer

IP.com Disclosure Number: IPCOM000074927D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Schwartz, AA: AUTHOR

Abstract

In order to eliminate the time penalty of the disc (video refresh storage) to Raster Assembly Store (RAS) transfer feature in Digital Television (DTV) systems, both the RAS to disc and the disc to RAS transfers are done simultaneously.

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Two Way Sequential Transfer

In order to eliminate the time penalty of the disc (video refresh storage) to Raster Assembly Store (RAS) transfer feature in Digital Television (DTV) systems, both the RAS to disc and the disc to RAS transfers are done simultaneously.

The process of recording and reading back from the disc introduces delays, which would prevent the writing of the nth word of a first channel into the RAS when the nth word of the second channel is read out of the RAS for recording on the disc. Therefore, simultaneous transfer is accomplished by writing an earlier word, of the second channel, n-1 for example, into the RAS location of the nth word of the first channel, while the nth word of the first channel is being transferred to the disc.

Simultaneous transfer is accomplished by the system as shown. A RAS-to- disc transfer command specifies both the channel to be written on disc 2 and the channel to be read, as well as such other information as destructive or nondestructive readout. Since an earlier (n-1)th word of the second channel is written into RAS 1 location of the nth word of the first channel, when the nth word of the first channel is transferred to disc 2, the data in RAS 1 processes without a similar precession in the disc. This precession in RAS 1 is accomplished by wraparound in RAS 1 in which the last word from disc 2 is put into the first location in RAS 1. For a normal DTV RAS address to access the correct data in RAS 1, the location por...