Caption: FIGURE 6: The file reading time in sequential access
A virtual object contains the worst values seen in each sequential access
We modify the transaction data for R1 and R2 from the respective examples by making the first two transactions as insert / deletes and the next two transactions as sequential access
To recoup the added cost of a disk library, it should deliver high enough sequential access
to replace ten or more tape drives.
Host Data Connect already supported the main IMS database organizations - HISAM (Hierarchical Indexed Sequential Access
Method), HIDAM (Hierarchical Indexed Direct Access Method), HDAM (Hierarchical Direct Access Method), SHISAM (Simple Hierarchical Indexed Sequential Access
Method), HSAM (Hierarchical Sequential Access
Method) and SHSAM (Simple Hierarchical Sequential Access
7V, sequential access
Flash memory device that features a 40MHz Rapids[TM] serial interface with SPI compatibility and a 20 MHz Rapid8[TM] 8-bit interface.
Some history is in order: The IT shop probably started life on the mainframe, using esoteric formats and languages such as VSAM (Virtual Storage Access Method), QSAM (Queued Sequential Access
Method) and COBOL (Common Business Oriented Language).
Specifically, VSAM (Virtual Storage Access Method), QSAM (Queued Sequential Access
Method) and Database 2 (DB2) data can be accessed -- on demand -- through intranets, extranets or the Internet, without requiring additional IT resources.
RBASE and dBASE have a behavior similar to COBOL where sequential access
without indices is much faster.
Using iSMART's disk usage information, such as read/write, random and sequential access
, and block sizes, users will also be able to verify that they bought the ideal product for their specific application, fine tune software settings for better performance, and even save money by ensuring that they choose the most suitable drives for their applications in the future.
Some architectural issues remain facing traditional tape storage and include: 1) the time to first byte of data (milliseconds for disk and seconds for tape); 2) tape supports sequential access
only (disk supports random and sequential access
); and 3) the recovery time for data is longer for tape than for mirrored or replicated disk (minutes or hours on tape compared to seconds normally for mirrored disk).