A rather confusing BIOS error message in personal computers when they were still called AT compatible or industry standard.

It would show up when you would try to boot with no floppy disk in the drive and the hard disk did not have any partition flagged as active.

The original IBM PC still had a ROM basic, as well as a port for a cassette drive.

Yes, I admit that it cost me about an hour to find out what had happened when this error first hit me.

The ROM Basic Not Found error was typically the first error message that would present itself when one upgraded to a SCSI system. The error was rather cryptic, and most SCSI-newbies assumed that the SCSI ROM was not set correctly, so they'd spend hours re-configuring jumpers in a futile attempt to make the SCSI card "work".

Low-level formatting a SCSI drive using the built-in SCSI ROM program, then formatting it using a floppy disk with FDISK and FORMAT on it would get rid of the message. Unfortunately, many SCSI card manufacturers forgot to include this error in their documentation.

Installation of SCSI drive systems brought in about $2K in 1995 when I had a small business. I still get emails from folks I know who don't understand why they need BASIC installed on a drive to make it work :)