The Jasik Debugger was a debugger

Debugger

A debugger or debugging tool is a computer program that is used to test and debug other programs . The code to be examined might alternatively be running on an instruction set simulator , a technique that allows great power in its ability to halt when specific conditions are encountered but which...

 tool for the classic Macintosh

Mac OS

Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...

 operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

. Pitched as a much more powerful alternative to Macsbug

MacsBug

MacsBug is a low-level debugger for pre-Mac OS X Macintosh operating systems. MacsBug is an acronym for Motorola Advanced Computer Systems Debugger, as opposed to Macintosh debugger...

, it was the debugger of choice among professional Mac developers until the advent of more advanced source-level debuggers such as that built into Metrowerks

Metrowerks

Metrowerks was a company that developed software development tools for various desktop, handheld, embedded, and gaming platforms. Its flagship product, CodeWarrior, comprised an IDE, compilers, linkers, debuggers, libraries, and related tools...

 Codewarrior

CodeWarrior

CodeWarrior is an integrated development environment for the creation of software that runs on a number of embedded systems. Prior to the acquisition of the product by Freescale Semiconductor, versions existed for Macintosh, Microsoft Windows, Linux, Solaris, PlayStation 2, Nintendo GameCube,...

.

While Jasik's debugger featured a graphical user interface

Graphical user interface

In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

, it was laid out in a very arbitrary and peculiar way, with buttons seemingly randomly sized and positioned. This gave it a reputation as difficult to use.