Amdahl Corp, Sunnyvale, California says its 4.5Mbyte-per-second High Speed Channel Feature and larger cache memory sizes are now available. The fast channels are available on the Fujitsu-sourced 6680 disk drives, which Amdahl claims give up to tenfold improvement in input-output response times over conventional disk subsystems even when operating at the 3Mbyte per second channel rate, and up to 12-fold improvement at 4.5Mbps. The High Speed Channel Feature is also available for the Amdahl Cache Controller Feature, which can improve response times 50% to 70% on its own, and by 60% to 80% with the fast channels. Use of 1Mbit memory chips means the cache can now be up to 128Mb against 32Mb previously. The High Speed Channel Feature is $20,000 per disk subsystem or cache device and $25,000 per four-channel group of a 580 Series processor. 6880 Cache is currently available in 8Mb, 16Mb and 32Mb sizes; 48Mb and 64Mb will be out in September, 96Mb and 128Mb in the first quarter 1988; 64Mb Cache will be $306,900.