With manufacturing well underway, the LaserWriter was crashing.
After a brief interlude at the Hawaii sales conference, the team was back at work finishing the software that would let the LaserWriter print from Macs connected to it through an AppleTalk network. There were a number of pieces:
- Printer driver software on the Mac, to take Mac documents and convert them to Postscript for the LaserWriter
- AppleTalk software on the Mac and LaserWriter to get the Postscript document from the Mac to the LaserWriter
- Utilities on the Mac to let users name the printers on their AppleTalk network and select the one to print to
- LaserWriter firmware to interpret and print the document
The Mac systems team was hard at work at Apple on the print driver and utilities. People at Adobe were hard at work on Postscript and other components of the LaserWriter itself. And Alan was hard at work on AppleTalk at both places.
The LaserWriter was going to be announced at the Apple shareholders meeting in late January, 1985. Unlike the Mac, it did not have a floppy disk or other way to install software; its “firmware” was built in through a read-only memory (ROM) chip. The ROM was a “critical path” component in the LaserWriter’s production and had to be ready well ahead of time.
In late 1984, or perhaps very early 1985, testing was completed, the LaserWriter firmware was “frozen” and “burned into” the ROM, and LaserWriter manufacturing began. The software on the Mac side still had a bit more time to be tested and finalized.
Cupertino, we have a problem. The Mac LaserWriter software included a “Namer” to set the printer names, and a “Chooser” to select the printer to print to. Testing of these utilities with early production LaserWriters would once in a while cause the LaserWriter to crash, restart, and print out its initial test page.
What was going on? It turned out there was a bug in the LaserWriter firmware. Names of a certain length would cause the crash (nerdy technical detail: if length mod 4 = 1 then crash). What was to be done? The problem couldn’t be fixed through a new LaserWriter ROM without costly disruptions to its production and a major schedule slip.
The solution: don’t let the name of any LaserWriter have any of those lengths! The Mac’s Namer utility was not yet finalized, so it could be changed to “fix” the bug. The next problem: no one wanted to have to tell LaserWriter administrators they couldn’t use certain seemingly random names.
Part 2 of the solution: if the name the administrator wanted to use was the “wrong” length, secretly add an invisible “space” character at the end of the name! The LaserWriter wouldn’t crash, and no one would be the wiser.
The rest, as they say, is history. The LaserWriter was announced and shipped on time (more or less), as a key component of the “Macintosh Office” (see upcoming post). The bug was later fixed in the ROM and rolled into production, and if the Namer detected a LaserWriter with the new ROM, it didn’t need to add the space any more.
PS (yes, postscript). AppleTalk and the LaserWriter, like the Mac, were designed to be “plug and play” (in fact we may have invented the term). In particular, users never had to type in the name of the device they were using. Instead they ran utilities like the Chooser which used an AppleTalk-invented feature to determine and list the names of available devices, which users could then choose from. If users had had to type in the name of their LaserWriter, this solution wouldn’t have worked.