A data compression product from Stac Electronics, called Stacker, is now available for IBM PCs and compatibles. Stac Electronics claims that Stacker can double disk storage capabilities. The product is available as software for laptop, notebook, and micro channel-based computers; as an add-in board plus software for PCs, XTs, ATs, and compatibles; and in coprocessors for OEMs. Stacker provides realtime, loss-less compression at ratios ranging from 2:1 to 15:1.
DDJ talked with Gregory Thomas of Southern California Edison, a beta tester for the product. "It works real well. There are two different ways you can use it--one way is called free space, and it sets up a virtual hard disk and creates another drive. The other way is called incremental, and it takes a full disk and compresses it, also to create another drive. I've used it on several machines, and it works with Windows. It compresses text files better than spreadsheet files, though. With spreadsheet files the compression ratio is something like 1.7:1."
The compression and decompression process is continuous, transparent to users. Stacker is a 30 Kbyte program you can load into high memory with a memory manager utility. The coprocessor card fits into an ISA expansion slot and requires no switching. The software-only version sells for $129 and comes with a $100 coupon for the coprocessor board. Board and software together sell for $229. Reader service no. 20.
Stac Electronics 5993 Avenida Encinas Carlsbad, CA 92008 619-431-7474
Bloomsbury Software Group is now shipping the ydb symbolic debugger for yacc grammars and parsers. A grammar development tool, ydb offers interactive environments for grammar debugging and parser generation on Unix systems.
The company claims it is 100 percent backward-compatible with yacc, so it can be used for debugging yacc grammars or for creating more flexible parsers than yacc can generate. ydb has been used to help with research in grammars for image recognition.
Ronnie Kon, project manager at Mind-craft of Palo Alto, California, told DDJ "I wish I'd had it sooner--it could have saved me a lot of time on a project I was working on. It has a friendly way of specifying how you want a conflict in syntax resolved. Yacc is bad about giving debugging help; so ydb sits on top of the grammar and interprets it. There's nothing else like it that I'm aware of."
A set of tools for producing grammars at translate time is included, as is debugging control of an operating parser at runtime. It also gives you the ability to trace parser actions and set breakpoints at particular rules or other points in the parse. The company is marketing ydb to developers and maintainers of compilers, command interpreters, and front ends, as well as to educators who teach compiler and parser courses, and to researchers who use experimental grammars for pattern recognition. ydb is now available for Sun 3, Sun 4, and DECstation computers, and is being ported to others. Prices start at $1,250 for a single CPU license. Academic and quantity discounts are available. Reader service no. 22.
Bloomsbury Software Group Inc. P.O. Box 390018 Mountain View, CA 94039 415-964-3486
libhpgl.lib, version 5, is a 32-bit 386 protected-mode extended graphics library from Gary R. Olhoeft. The library supports graphics direct to hardware for IBM standard modes EGA/VGA/MGA/8514, VESA/SVGA, Hercules Graphics Station Card GB1024, Truevision ATVista-4M, and WYSIWYG hardcopy to HP-GL and PostScript devices or files.
libhpgl.lib supports mixed-vector plotting and raster imaging, graphics viewports (partial screen windowing), user unit scaling, rotatable and scalable labels, and more, up to 1024 x 768 with 8-, 16-, or 32-bit graphics cards (256, 32,768, or 16,777,216 colors).
The library comes with full source code in MicroWay NDP C-386 and Phar Lap 386/ASM, extensive example code and manual, free upgrades for one year, and no royalties. libhpgl.lib is priced at $200. Reader service no. 23.
Gary R. Olhoeft P.O. Box 10870 Edgemont Golden, CO 80401-0620 303-279-6345
If you are developing device drivers for multiprocessing under SCO Unix, you might be interested in the technology Corollary has developed for multi-threading serial I/O device drivers under SCO MPX, the multiprocessing version of Unix for running off-the-shelf applications and serial I/O device drivers. Corollary will soon ship a multithreaded version of the device driver for its 8x4 and 8x2 multiport boards. The company expects this technology will produce higher performance of SCO Unix-based multiprocessor systems that utilize multiport boards to support multiple users. Reader service no. 24.
Corollary Inc. 17881 Cartwright Rd. P.O. Box 18977 Irvine, CA 92714 714-250-4040
A grey-scale and full-color image compression software package is available for PCs from Xing Technology. VT-Compress is a complete implementation of the ISO/CCITT JPEG standard for still image compression and transmission. JPEG is an international group of data compression experts formed in 1986 by ISO and CCITT. Their task has been to reduce image storage requirements and transmission times. The JPEG Baseline Algorithm uses "lossy" compression techniques to remove redundant information from the digital storage of grey-scale and full-color images. The company claims that VT-Compress can compress at ratios of up to 100:1, and that images compressed at ratios of 8:1 to 20:1 are for the most part indistinguishable from the originals. VT-Compress optimizes the use of registers and instructions of the 80286 and 80386 microprocessors, and is priced at $179. Reader service no 25.
Xing Technology Corp. P.O. Box 950, 456 Carpenter Canyon Arroyo Grande, CA 93420 805-473-0145
JAM (JYACC Application Manager) version 5 is the centerpiece of JYACC's product family for prototyping and producing applications that are hardware, operating system, database, and network independent. This new version of JAM has been optimized for PC use with full mouse support, extended graphical character sets, use of foreground/background color, and line drawing.
Other new features include virtual screens, viewports, mouse support, radio buttons, checklists, and scroll bars. These features give character-based applications a graphical look-and-feel without added memory or hardware costs. 8-bit internationalization allows JAM developers to create applications for use with languages that are read from left to right and that use characters represented in 8 bits of information. Screen editor facilities include clipboards and block, move, and copy for manipulating data objects in a form. Used with JAM/DBi, JAM applications can be seamlessly linked to 11 relational databases. Prices are $595 for DOS, $1,350 for OS/2, and $1,950 for Unix/386. Call for pricing on other platforms. Reader service no. 26.
JYACC 116 John St. New York, NY 10038 212-267-7722
The Real Time Consortium (RTC) has been formed from realtime operating system and kernel vendors Ready Systems, Wind River, Lynx Realtime Systems, and Eyring Research Institute, and from high-performance computer board vendors Heurikon and FORCE Computers. RTC seeks to support existing global standards within industry organizations and to develop new standards at the appropriate hardware interface and application level. RTC was formed by the growing demand to establish interoperability between different hardware products and various realtime kernels and operating systems.
The first project of RTC's Technical Committee was to develop a preliminary specification for an Open, Basic Input Output System (OBIOS). DDJ spoke with Greg Buzzard of Ready Systems, who is chairman of that committee. He said, "As drivers become more complex and as the number of drivers grows the problem worsens. The OBIOS implementation will provide device-dependent parts of a device driver. It will be the interface between the operating system part of the code and the physical devices. Instead of targeting specific I/O devices, board and software vendors will target the OBIOS."
The OBIOS standard's physical I/O interface cuts the time necessary to program device drivers. The intent is for the OBIOS to eliminate the need to continuously rewrite device driver modules for each combination of hardware and operating systems or realtime kernels.
RTC seeks technical input and design commitments from chip, hardware, and software companies, as well as from users throughout the industry. Buzzard said, "Our goal is to go to IEEE ballot by the first quarter of 1991. We expect to have a draft ready by January that the working group is willing to accept public comment on." If you would like to obtain the draft, you may download data from the Internet via anonymous file transfer protocol from the RTC directory at gate.ready.com. If you wish to write to the RTC, contact
Shohat & Kahn PR 1875 Winchester Blvd., Ste. 203 Campbell, CA 95008 408-379-7434
ARC+Plus 7.1, a file compression program formerly available as shareware, has been revised and is supposedly now even easier to use. SEA (System Enhancement Associates) has upgraded ARC+Plus, which features pull-down menus, mouse support, backup options, auto-self-extraction, portability of files to other operating systems, and tight compression.
Former shareware users can upgrade for $34.95 by sending in the system disk. The retail price for ARC+Plus 7.1 is $89.95. SEA is seeking retail distribution because of the cost involved in publishing and upgrading a program and supporting its customers. Reader service no. 29.
SEA 925 Clifton Ave. Clifton, NJ 07013 201-473-5153
Copyright © 1991, Dr. Dobb's Journal