Image files can consume large amounts of disk space that cost roughly $1 per megabyte. By contrast, files can be stored on DAT tape for less than 1 cent per megabyte for a 2 gigabyte tape cassette! Two new TAPEDISK Software products now make it easy to use HP35480A DAT tape drives with EPIX menu-driven and object code software.
TAPEDISK DOS Access Program
The new TAPEDISK DOS Access Program, from the TAPEDISK Corp., allows 4MIP/ SVIP direct access to Hewlett Packard DAT, and other tape drives. TAPEDISK allows a tape drive to be accessed as a DOS file system; i.e. as just another "disk drive" such as "D:"-with slower access but much larger capacity.
With other DOS-based tape access programs, generally designed for file backup and restore, tape access is available only from within the tape access program. Typical tape access programs only copy files to and from the hard disk. To capture and save a 64 megabyte sequence of images requires:
This is inconvenient and assumes that 64 megabytes of hard disk is available for temporary use!
The TAPEDISK program brings to PC DOS the type of data set transparency common on more sophisticated operating systems: program access to disk or to tape using identical procedures. SVIP/4MIP doesn't even need to know that a tape is being used; users can perform a directory search, and load or save image files, just by prefixing the appropriate drive letter, such as "D:" to a file name. TAPEDISK, together with DOS, provides transparent device access to tape in much the same way that DOS alone provides transparent access to either a diskette or a hard disk.
DAT Tape Provides an Inexpensive Alternative To Hard Drive Storage - Worth Considering When Gigabytes of Images Must Be Archived!
TAPEDISK requires Expanded Memory (EMS) with a 64K page frame. Since EPIX imaging boards require a 64K segment for image memory access, a successful configuration requires a PC with two unused segments. On newer 386 or better machines, both the D0000 and E0000 segments may be available. Or, if VGA graphics aren't being used, the A0000 and D0000 segments may be unused. Microsoft's MSD.EXE utility can help determine PC configuration and segment availability.
TAPEDISI I/O Object Code Library
The second new product is TAPEDISK I/O Object Code Library (TIO) which allows programmers to implement non-DOS access to HP35480A DAT tape drives. TIO is useful for archiving or recording large numbers of images. Data rates are approximately ten to thirty megabytes per minute. A typical use would be automated testing of imaging algorithms using imaging inspection data recorded during a long manufacturing process.
Because DOS and WINDOWS are single-threaded systems, which require one I/O operation to finish before another is started, (which could take as long as forty seconds with TAPEDISK DOS Access Software) TIO is a better alternative for faster storage rates. TIO completely bypasses DOS and permits the developer to command and check DAT tape deck operation, independent of DOS, to initiate and verify tape deck operations. Thus, data analysis, disk I/O and DAT tape processing can overlap.
TIO is being developed jointly by TAPEDISK CORP and EPSTEIN ASSOCIATES to complement EPIX object code libraries. EPSTEIN ASSOCIATES is an EPIX distributor and system integrator specializing in automatic image analysis manufacturing inspection systems. TIO will be initially available for use with the HP35480A DAT drive and the Microsoft C Version 7 Compiler.
For more information about TAPEDISK Software, HP DAT drives, and other tape drives supported by TAPEDISK, contact:
EPIX Vision - October 1993 Newsletter