Cassette for IBM PC and related systems

[krebizfan]

This is to be a partial list of all known mass-produced systems and cassette tapes for the IBM PC or something related.
With cassette port
IBM: PC, Jr, and JX
Advance 86: Near clone of IBM PC with 8086 processor. Not only had cassette port but also copy of Cassette BASIC until IBM complained.
Soviet: Poisk I, MC1502, MK88 The first two used different extensions to the IBM cassette format; the third used MSX cassette format
Not trying to be PC compatible:
Mutlitech MPF-1/88 A trainer that followed the Apple IIc look. Had its own cassette routines but also could read/write IBM PC cassettes. With the addition of an external expansion board and video, RAM, and diskette controller cards, it could be turned into a near XT system.
Sharp PC-5000: Bubble memory and built in printer gets all the notice but the cassette port is still there.
Alpatronic PC16: A keyboard PC that surprisingly retained a cassette port. My entire source for this is a German Wikipedia page. Could be wrong.

Software
IBM PC
The IBM Diagnostic and Advanced Diagnostic cassettes are the only ones known to have been produced.
Advertised but no known copies exist
Microsoft Typing Tutor
Homecomputer Magazine typein listings for the PCJr

Other Machines
Advance 86 was supposed to come with a Welcome cassette with a simple program to tell you that it loaded from cassette and a number of small games. No copies are known.
Soviet: About 15 cassettes were mass produced. 10 with games, 3 with programming languages, another 2 with small applications. May be more.

Basicode was a European effort to create a single format that could be used to broadcast programs over radio to many different types of computers. There was a mass produced parallel to cassette port adapter for systems that lacked a cassette port. The software was overengineered somewhat. It replaced the cassette routines with cassette routines that could read and write both the Basicode format and the IBM PC format, even for systems that used the parallel port adapter.

 

[voidstar78]

While the Sharp PC-5000 does have a cassette interface port on the back, the Microsoft BASIC on that system has no keyword to actually make use of it. I don't think WordStar or SuperXYZ office application make use of it either (i.e. no "save to tape" option).

Page 34 of the Service manual (section 2-36) I see what might be a description of the CAS interface pins of whatever chip drives that - it describes pin 21 and audio input, pin 22 audio output, pin 23 send data output, pin 24 receive data input. So it seems there is some hardware behind those pins, but I've no idea what hardware ports or software API is available for actually making any use of it.

 

[krebizfan]

For the Sharp PC-5000, IIUC the design, at startup, provides the option of using the BASIC in ROM could be chosen which would access the cassette port as the only storage medium. It won't access the bubble memory or other drives since DOS was not loaded. That information could be incorrect. I lack a physical unit to confirm.

Whether there was some way to transfer from cassette to disk is something I can't prove. I don't have a good source of information on the Japanese market 40 years ago.

As a further followup, links for the Alphatronic follow
https://retroordenadoresorty.blogspot.com/2018/04/ta-alphatronic-pc-16-1985.html
https://de.wikipedia.org/wiki/Alphatronic_PC16
archiv computeum has a few manuals for the BTX version of the system BTX was a videotext style service and the BTX module connected to a modem and the CRT. Otherwise, a module that almost supported CGA could be installed.

 

[voidstar78]

I have two PC-5000's, and indeed, it is not a normal "boot to BASIC" system despite having a BASIC ROM cartridge. The manual (Chapter 5) explains why:



When it says "earlier version" I'm not sure how early it is talking (for example, does it mean pre-production "prototype"?) Despite not being very popular (here in the US), the system was still sold at least until 1987 - so maybe some earlier production systems did boot to a simpler ROM BASIC. So far I haven't come across anyone with this fabled earlier version of the PC-5000.


The BASIC (for the PC-5000) isn't in a single ROM like we normally think of it. In this system, they split the BASIC across two components: (#1) the BASIC ROM cartridge at the bottom of the system, but then (#2) also a part of it is located in an additional ROM inside *each* bubble memory cartridge (that contains the BASIC.EXE needed to actually launch BASIC). So, if you don't have at least one bubble memory cartridge (or a disk drive), you won't be able to invoke its BASIC even if you have the BASIC ROM cartridge. [ and for some reason that BASIC.EXE is 61,440 bytes - so it's not like it is just a loader to the actual ROM BASIC; but I haven't disassembled to look into why the bubble-memory BASIC.EXE depends on that ROM BASIC at all - since indeed if you remove the bottom mounted ROM BASIC cartridge, then the bubble memory BASIC.EXE no longer works; it's like it is a BASICA.COM and GWBASIC.EXE hybrid of some sort -- which sort of makes sense, as GW-BASIC development was done right in there at 1983 ]


But then the SAVE command only goes to a bubble cartridge or disk files, there is no "CSAVE" or way to direct saving to the cassette port. Unless there is some undocumented way; I've poured over the Sharp manuals looking for a way. I can't recall if MS-DOS 2.0 had software interrupts to save/load from tape (the system is DOS 2.0 compliant, but otherwise not quite IBM PC compatible).

Anyway, sorry to distract your thread on issues about this one particular system. But the PC-5000's support for cassette needs an asterisks, reminding that despite the hardware being there, no known software exists to support it (including not in the BASIC ROM). But I certainly wouldn't mind being proven wrong on that (I'm not fluent in Japanese to ask in any Japanese-language forums,).