Commodore 128 native software

Commodore 128 native software is, in this article, software whose release evidence (its own manual, packaging, advert or review, or Commodore documentation that names it) places it in the native C128 operating mode of the Commodore 128, as distinct from programs the same machine runs in its CP/M or Commodore 64 environments. Commodore's documentation describes the computer as offering three primary modes, C128, C64 and CP/M, each with its own processor role, BASIC or operating system and display options. Because many of the adverts and listings consulted labelled a product "128" or "64/128" without saying which mode it used, the article sorts every title in its sample table into one of four classes: native 128-mode, CP/M mode, runs only in C64 mode, and mode not stated in the sources.

Modes as the basis for classification

Commodore's manuals treat the three environments as separate working contexts rather than as features of one system. The System Guide gives each mode its own chapter and tells readers that C64 mode is the place for existing Commodore 64 packages, while CP/M mode opens a separate body of CP/M software. In the Programmer's Reference Guide, native mode is defined by the 8502 at 1.02 or 2.04 MHz, the C128 Kernal, BASIC 7.0 and both 40- and 80-column output; C64 mode by the same processor held at 1.02 MHz with the C64 Kernal, BASIC 2.0 and 64K of RAM; and CP/M mode by the on-board Z80 running a disk-based CP/M 3.0.

The same chapter is candid about the trade-off: an owner working in C64 mode gives up the 80-column editor, the older BASIC there has no access to RAM beyond the first bank, and none of the newer facilities can be used. David L. Heiserman's reference guide adds the reason the compatibility environment exists: in his account, many programs written for the Commodore 64 would not work properly under the C128's normal configuration, so Commodore built C64 mode into the machine. A fuller account of each environment is given in Commodore 128 operating modes.

Inclusion rule

The rule used here is an editorial test built on the manuals' three-mode model; it is not a classification taken from any source consulted. A title is assigned to exactly one class from what its release evidence says about the mode in which it runs. That evidence is either the title's own manual, packaging, advert or review, or Commodore documentation or marketing that names the title together with a mode:

• Native 128-mode: the evidence says the title runs in C128 mode, or that it depends on facilities the manuals reserve for that mode, such as BASIC 7.0 or 2 MHz (FAST) operation.
• CP/M mode: the evidence identifies the title as CP/M software, which is run only after CP/M has been loaded from its system disk.
• Runs only in C64 mode: the evidence directs C128 owners to C64 mode and offers no C128-mode version.
• Mode not stated: the evidence ties the title to the C128, or to both machines, but never says which mode it uses.

Two kinds of evidence are deliberately insufficient for the native class. A disk that starts itself is not enough, for the reasons given in the next section. Nor is a model number in the product name, a "for the Commodore 128" label, or the publisher's other C128 products; such titles fall into the fourth class unless more is said. Where one release contains separate C64 and C128 versions, the class describes the C128 version.

Start-up and boot behaviour

Starting a program automatically is a loading mechanism, not a statement of mode. The Programmer's Reference Guide describes the Kernal BOOT routine as reading track 1, sector 0 of a disk, checking it for an auto-boot header and, if one is found, loading further sectors or a named file and then calling the code held in the boot sector; after BASIC finishes its cold start, the PHOENIX routine first calls any installed C128 cartridges and then checks unit 8, drive 0, for a disk of that kind. Heiserman's guide treats the BASIC keyword BOOT in the same way, as a command whose job is to load machine code off a disk and launch it.

One self-starting disk shows why the rule excludes boot behaviour. On Heiserman's account the CP/M System Disk boots itself, whether the trigger is switching on, pressing reset or typing BOOT, and what appears is the A> prompt of CP/M rather than a C128-mode screen. No copy of CP/M is resident in the computer; it is loaded into RAM from that disk, after which the Z80 replaces the 8502 as the working processor. A boot sector therefore says how a program begins, not which of the three environments it occupies.

Start-up can also push the machine the other way. The Introductory Guide gives three ways into C64 mode: switching on with a C64 cartridge already fitted, which then starts the cartridge program; holding down the Commodore key at power-on; and typing GO64 from C128 BASIC. The mode chart in the Programmer's Reference Guide records the same three paths and lists the absence of a CP/M system disk and of a C64 cartridge as conditions for a normal start in C128 mode. Heiserman adds that otherwise the C128 always starts in its own mode.

Classified titles

The table applies the rule to every title the article classifies. Five entries, JANE, WordStar, dBase II, The Perfect Series and the Magic Voice speech module, are classed from Commodore's manuals, brochure or Buyer's Guide machine entry, not from the product's own release material, which was not found among the sources consulted; Magic Voice, a module fitted to the expansion port rather than a program, is included because the System Guide states the mode it needs. Three products are mentioned only in passing and are left unclassified because they fall outside the sample: the C-64 edition of PaperClip, GEOS and the CP/M 2.2 cartridge. The table is a sample drawn from the sources consulted, not a catalogue of C128 software.

Title	Release evidence	Class
JANE	Commodore's Introductory Guide, three-modes summary	Native 128-mode
Symbol Master (Schnedler Systems)	Advert, COMPUTE!'s Gazette, August 1986	Native 128-mode (C128 version)
BASICally SIMPLE 128 (Free Spirit Software)	Advert, same page	Native 128-mode
Fontier 128	Type-in program and article, COMPUTE!, December 1986	Native 128-mode
Adams Software program collection	Listing, Buyer's Guide, Winter 1986–87	Native 128-mode (C128 version)
WordStar	Commodore brochure; Buyer's Guide; Programmer's Reference Guide	CP/M mode
dBase II	Commodore brochure; Buyer's Guide	CP/M mode
The Perfect Series (Perfect Writer, Perfect Calc, Perfect Filer)	Brochure; Buyer's Guide; Introductory Guide; contradicted by Programmer's Reference Guide	CP/M mode (one Commodore source disagrees)
Arithmetician (tensoft)	Listing, Buyer's Guide	Runs only in C64 mode
Music of the Masters, volumes I and II (Free Spirit Software)	Advert, COMPUTE!'s Gazette, August 1986	Runs only in C64 mode
Magic Voice speech module	Start-up advice, System Guide	Runs only in C64 mode
The Bard's Tale (Electronic Arts)	Advert, COMPUTE!'s Gazette, August 1986	Mode not stated
PaperClip II (Batteries Included)	Adverts, COMPUTE!, December 1986	Mode not stated
The Consultant (Batteries Included)	Advert, COMPUTE!, December 1986	Mode not stated
Pocket Writer 2 (Digital Solutions)	Listing, Buyer's Guide	Mode not stated (C128 version)
Fleet System 4	Listing, Buyer's Guide	Mode not stated
Flex File 128 (Cardinal Software)	Listing, Buyer's Guide	Mode not stated
CMS Inventory 128 and CMS Accounting System (CMS Software Systems)	Listings, Buyer's Guide	Mode not stated (C128 version of the Accounting System)
Fontmaster 128 (Xetec)	Listing, Buyer's Guide	Mode not stated
COMPUTE!'s First Book of the Commodore 128 (COMPUTE! Books)	Advert, COMPUTE!, December 1986	Native 128-mode

Native 128-mode

Commodore's own Introductory Guide supplies a manufacturer example: it cites the integrated package JANE as the kind of sophisticated application that the 128K of C128 mode is meant to run. Among third-party releases, the Schnedler Systems advert in the August 1986 COMPUTE!'s Gazette says its Symbol Master disassembler ships with native-mode versions for both the C64 and the C128, and the Free Spirit Software advert on the same page describes BASICally SIMPLE 128 as a tutorial on BASIC 7.0 supplied on a disk for 128 mode. Adams Software's entry in the Winter 1986–87 Buyer's Guide is explicit as well: its four-disk collection of 110 programs came in a C-128/1571 edition, marked for use in C-128 mode, alongside a C64/1541 edition.

Fontier 128 appeared as a type-in listing in the December 1986 COMPUTE!, and its article ties it to native mode in three ways: the editor leans on the 128's screen windows, it works at the FAST setting and so needs an 80-column display, and each saved font is itself a file that 128-mode BASIC can RUN. The same article says the resulting fonts can also be installed in CP/M and C64 mode, so the editor is native while its output spans all three environments.

CP/M mode

Both the brochure and the C128 hardware entry of the Buyer's Guide name WordStar, dBase II and The Perfect Series among existing CP/M packages open to a C128 owner, and the Programmer's Reference Guide, too, puts WordStar under CP/M mode. Perfect Writer, Perfect Calc and Perfect Filer appear as sample programs in the Introductory Guide's summary of CP/M mode. Such programs are run by first booting CP/M Plus, then swapping in the program disk and typing the program's name at the prompt. Running on a C128 does not make these titles native; they are classed by the environment they need.

Runs only in C64 mode

Arithmetician, from tensoft, is listed in the Buyer's Guide for the Commodore 64/128, but with a note restricting it to C-64 mode. Free Spirit Software's two Music of the Masters disks are offered for the C64 or for a C128 in 64 mode, in the same advert that sells a 128-mode disk, which shows one publisher marking the distinction title by title. The System Guide's start-up notes handle the Magic Voice speech module in the same spirit: with the module fitted, the owner keeps the Commodore key down as the power comes on, which is the route into C64 mode.

Mode not stated

The largest group carries a C128 identity without saying which mode it uses. Electronic Arts offered The Bard's Tale for the "C-64 & 128", and its specifications give two disks and a 64K RAM minimum; nothing in the advert names a mode, so the title is not assigned to the C64 class. Batteries Included sold PaperClip II as being for the Commodore 128, able to read C-64 PaperClip files, with the advert saying it had been "re-designed to take full advantage" of the newer machine, and marketed The Consultant for the Commodore 128/64; neither advert names a mode.

The Buyer's Guide shows the same pattern. Its Pocket Writer 2 entry puts the 128 and 64 versions on opposite faces of one disk, while the Fleet System 4 entry claims only Commodore 128 compatibility. Flex File 128 names a C128 and a 1571 drive as its required hardware, accepts any monitor and promotes 40/80-column operation as a feature; CMS Inventory 128 calls for an 80-column RGBI monitor; the CMS Accounting System gives separate hardware lists for a 128 system and a 64 system; and Fontmaster 128 is simply marked for the Commodore 128. These listings specify hardware rather than a mode, so the titles stay in the fourth class.

How releases expressed platform identity

Commodore's guidance pointed users to each product's own documentation. The Introductory Guide tells users to pick the mode the software requires before loading it and to follow the program's own manual, and it notes that disks served all three modes, cartridges both the C128 and C64 modes, and cassettes only those two. In the adverts and listings consulted, release statements varied in precision. The most exact releases named the mode, as with the Adams collection, BASICally SIMPLE 128 and Symbol Master; others named a hardware requirement, such as a 1571 drive or an RGBI monitor; and many stopped at a machine name or a combined "64/128" label.

Contemporary publishers sometimes stated modes for printed material too. A December 1986 COMPUTE! advert for the publisher's Commodore 128 book line says every program in those books is used in 128 mode, and describes COMPUTE!'s First Book of the Commodore 128, which had an optional program disk, as working only in that mode; under the rule, that book's programs are native 128-mode. Commodore's marketing, by contrast, spoke of the whole machine: its brochure promises complete compatibility with C64 software and access to existing C64 and CP/M 3.0 programs, while presenting the three modes in separate panels. The claim that the C128 "runs" a program is therefore a statement about the machine, and the manuals' separate mode chapters are the evidence that such a program may still need C64 or CP/M mode.

Conflicts and limits of the evidence

Commodore's sources do not agree about The Perfect Series. Three of them, the brochure, the Buyer's Guide and the Introductory Guide, file it under CP/M; the Programmer's Reference Guide, in its discussion of the 80-column chip, instead counts the Perfect programs among business software for C128 mode and keeps WordStar as its CP/M example. This article follows the three sources that agree and records the disagreement rather than resolving it.

Page numbers given here for the Buyer's Guide follow its printed index. No source consulted offers a complete C128 software list with verified modes, and the class for each title above rests only on the cited document; a manual or box not seen here might state a mode and move a title out of the fourth class. GEOS lies outside this sample, as does the separate CP/M 2.2 cartridge for the Commodore 64, which the System Guide tells C128 owners not to plug in and which the Programmer's Reference Guide rules out in every C128 mode.

See also

• Commodore 128 operating modes
• Commodore 64
• MOS Technology 8502
• GEOS on the Commodore 64 and 128
• C64 and C128 manuals as documentary sources
• Commodore BASIC

Automation and sourcing note

This article was independently synthesized from the cited sources under c64.wiki publication policy. Historical manuals and source archives were used as citation-only factual evidence; no source prose, code, images, scans, or screenshots were copied into the candidate.