taylorj@yvax.byu.edu (06/14/89)
Considering the many inquiries into HyperCard "clones" on the IBM PC, I think a brief description of IBM's LinkWay program will be benificial. I will make comparisons with HyperCard, since I think most people who are interested in this will be at least superficially familiar with HyperCard and would like to know how the two compare. First, LinkWay is not really a HyperCard clone. It's a graphic-based hypermedia tool that's similar to HyperCard. That is, it's a development system incorporating buttons, text fields, pictures, etc. It uses only 70K (HyperCard takes 393K), so it's much more limited than HyperCard but provides many of the same basic features. LinkWay runs on any IBM PC or compatible with a minimum configuration of 384K, a color display, mouse, and one floppy drive. It can use higher-resolution displays such as EGA or VGA and works better with more memory and a hard disk. LinkWay files are called "folders" and are roughly equivalent to HyperCard stacks. The system includes a separate paint program (LWPaint), an icon and font editor (LWFontEd), and text editor (LWEdit). The text editor can be integrated into LinkWay applications (text files can be up to about 25K). LinkWay applications are organized into "cards", just as with HyperCard. Each card can contain pictures (each picture is stored in a separate file on the disk), text fields (limited to 3K), and buttons. Each folder has a "Base Page" similar to a HyperCard background. Buttons and text on the Base Page are visible on every card in the folder. Each folder must fit in memory (with a 250K) limit, but folders can be linked together, limiting application size only to available disk space. LinkWay has seven button types: Go, Link, Find, Text Pop-Up, Picture Pop-Up, Script, and Document. Buttons can have icons attached to them. The pop-up buttons make pop-up-type displays easier to create than in HyperCard (but less flexible). Pop-up text and pictures are displayed in scrolling windows. Document buttons allow access to larger documents via LinkWay's text editor. Unlike HyperCard, only Script buttons can have scripts (programs); fields and other buttons have no scripts. The script language is spare but functional (there are about 40 commands). The only flow control is provided by IF/THEN and JUMP statements (repeat loops have to be constructed with these). There are no string-handling functions and math is limited. Reading and writing to disk files is supported and there are simple printing commands. Scripts can call other scripts, call external routines written in assembly language or high-level languages like C or Pascal, and can also give DOS commands to run other applications. The biggest difference in scripting is that LinkWay is not object oriented like HyperTalk. There is no message passing and no inheritance. Scripting is limited to single routines (no functions). LinkWay supports 4 color CGA (320x200), 16 color EGA and VGA (640x400), 256 color MCGA (320x200), and High Resolution Monochrome (640x400). The program automatically recognizes your display and can convert pictures from one display mode to another. Peripheral devices such as laserdisc players and video overlay cards can be controlled with the script language's SERIAL command or with custom-written external drivers. LinkWay's primary use so far has been in developing educational courseware, especially in the K-12 level. Some HyperCard developers are recreating HyperCard stacks with LinkWay. This is IBM's initial release of the program, and we can expect that it will be extended in future releases. LinkWay is available from IBM for $110. There is also a useful LinkWay ToolKit (created by the developer of LinkWay) available from Washington Computer Services, (206)734-8248, for $300. I take no responsibility for the accuracy of this report. (I havent used LinkWay yet, this is just a distillation of information Ive 'gathered.) Jim Taylor Microcomputer Support for Curriculum | Brigham Young University | Bitnet: taylorj@byuvax.bitnet 101 HRCB, Provo, UT 84602 | Internet: taylorj@yvax.byu.edu