IBM APEC

IBM APEC (IBM Advanced Portable Entertainemnt Computer) was the an IBM handheld console, and the sucessor of the IBM PEC. It was released in 1986, being somewhat expensive back then; it became cheaper and more popular than the IBM PEC around 1989-1991 when the 4th video game console generation started. Even though the IBM PS/2 was released 1 year later, it was intended to be the portable console equivalent to the PC/AT.

Cassette Player for APEC
Similarly to the Cassette Catcher for the original IBM PEC, this add-on can be inserted into the cartridge slot. Oddly enough, however, this isn't able to play any analog audio from the Cassette Tapes and can only load games on cassette format.

IBM Link
This link cable allows you to connect your IBM APEC to an IBM PC compatible PC, mainly intended for either updating the BIOS or to enhance certain games. You can also use this cable (with an adapter in the case of the official version) to link up with another IBM APEC like a Game Boy Link Cable, though very few games took full advantage of this feature.

The cable also allows you to connect with IBM PECs with at least version 3.0 of the BIOS, though even fewer games took advantage of this feature. The only program known to use this function was the BIOSes themselves, where you can transfer certain types of files from between an IBM PEC's connected cartridge and an IBM APEC's hard drive to allow you to play certain PEC games on an APEC without the cartridge.

Cartridge Adapter
While the IBM APEC is normally backwards compatible with the original PEC with the base cartridge slot, certain PEC cartridges with special hardware can't fit into the redesigned APEC cartridge slot. So this adapter came with the APEC to allow those special PEC cartridges to fit in. (Examples of PEC games with special hardware include "Power Quest (1985)" and "Alley Cat X (1987)".)

BIOS Updates
Similarly to the original IBM PEC, the APEC can have its BIOS updated via the IBM Link cable. Most BIOS updates released mainly updated the built-in version of the IBM OS/APEC, but some did include support for new peripherals.

Prototype versions

 * v0.5 (September 1985) - Shipped with a development kit for the IBM APEC to certain game developers. Doesn't include a menu, but unlike the IBM PEC BIOS v0.9, it can boot certain games like Microsoft Flight Simulator 2.
 * v0.9 (March 20th, 1986) - Uses IBM OS/APEC v3.2 (MS-DOS/PC-DOS 3.2 based). Otherwise fairly similar to v1.0.

Retail versions

 * v1.0 (March 25th, 1986) - Uses IBM OS/APEC v3.2a, though differences are unknown. Likely just a bug-fix version of v0.9, as it has a menu that is fairly different from later versions of the BIOS. Shipped with most IBM APECs from US Launch to November 1986.
 * v2.0 (November 2nd, 1986) - Doesn't update IBM OS/APEC, but does do a big overhaul of the system menu to make it somewhat more user friendly. Options like "MANAGE DATA" are changed to "File Manager" and the colors have been changed to be less eye-bleeding, and it also improves compatibility with the original PEC. Released as an update floppy disk bundled with certain APEC games released in late 1986.
 * v2.0j (November 5th, 1986) - The Japanese version of v2.0, aside from using a Japanese font and Japanese text it seems to be identical.
 * v2.1 (January 1st, 1987) - Updates IBM OS/APEC to 3.21, other differences unknown.
 * v2.1a (February 14th, 1987) - Adds in "native" support for the IBM PEC's TV Receiver.
 * v2.1b (Febuary 22nd, 1987) - Seems to fix some bugs with the native TV Receiver support.
 * v2.15 (Unknown date, Japanese only?) - Mentioned in an internal IBM document leaked in the 2000s. Seems to fix some issues with certain Japanese only games (A bootleg Japanese port of Bubble Bobble released onto a fan-game BBS is mentioned, which the bug-fix was likely originally only intended for as the other games that would of benefited from this bug-fix are unknown.) displaying the wrong colors due to incorrect video card initialization.
 * v2.2 (December 25th, 1987) - Uses IBM OS/APEC 3.21c, differences from v2.1b unknown aside from carrying over the bug fixes that were apparently in v2.15.
 * v2.4 (March 5th, 1988) - Uses IBM OS/APEC 3.30, adds in support for hard drives larger than 50MB. (Mainly sold by 3rd parties.)
 * v2.5 (April 21st, 1988) - Adds in "native" support for the PEC's "Video Output Cable with RGB" add-on. Also seems to be optimized for Microsoft's "Windows PEC".
 * v2.5a (September 1st, 1988) - Upgrades to a version of IBM OS/APEC based off of PC-DOS v4.01. Some memory hogging features of DOS v4.xx have been disabled by default, however.
 * v2.5j (September 5th, 1988) - The Japanese version of v2.5a, accidentally sets some different values in PEC backwards compatibility mode which was used by "The life of a slime" to add in new areas for the APEC.
 * v2.5z (December 1988) - Released worldwide, fixes the PEC backwards compatibility initialization issue of 2.5j except for if "The life of a slime" is detected as the inserted cartridge.
 * v2.5b (January 1st, 1989) - Adds in some cross-compatibility with the IBM APEC v1.2, which would be released later on in the same year.
 * v3.0 (March 1st, 1990) - Updates IBM OS/APEC to a version based off of an MS-DOS 5.0 beta.
 * v4.0 (November 16th, 1993) - Updates IBM OS/APEC to a version based off of PC-DOS 6.1. This would be the last BIOS update that updates IBM OS/APEC on the original IBM APEC.
 * v4.1 (December 25th, 1993) - Adds in "native" support for the remaining IBM PEC add-ons that were available at the time, the BIOS versions after this will simply do bug-fixes.
 * v4.4 (June 21st, 1995) - Fixes a few bugs related to sound initialization, causing the beeps to differ somewhat.
 * v4.5 (June 21st, 1996) - The final BIOS update, bug fixes are currently unknown.