As I've been considering getting one of these systems I already know a bit more about them (still, next to no information in English available).

Here's a Google Translated version of a fairly complete database of PC-98 systems and compatibles: With98 PC9800 Series information

There's a version of FreeBSD that can run on the platform: https://www.freebsd.org/platforms/pc98.html

Jo22 wrote:

PC98: Japanese PC platform (only partially compatible to IBM PC). Originally had C-BUS, later PCI. PC98 uses different memory layout.

Basically, PC98 uses Intel(-compatible) processors like the 286, 386, 486, and various 586/Pentium processors, but the architecture is sufficiently different (memory, video subsystem, floppy & hard disk drives, etc.) that it needs specific operating system versions. The system architecture uses a lot of daughterboards on the motherboard for various functions. Something important about C-bus (the NEC proprietary bus, plugs into the motherboard using a riser card) is that it was only used on PC-9801 systems and earlier, not on PC-9821 systems, as far as I've been able to figure out. The PC-9821 uses a proprietary bus similar to C-bus that might be electrically compatible with ISA and later PCI (the riser cards plug into ISA/PCI slots). Later PC-9821 had both the proprietary buses and regular ISA and/or PCI slots. This does not apply to Epson clones, those all use C-bus.

Later models are said to include a V20/30 co-processor for backwards compatibility.

Only specific models, I think. However, it is possible to get system cards that add support for different platforms, but those cards are rare as hens teeth. I've seen PC-88, PC-9801, PC-FX, & IBM-AT. There are also overdrive boards available that can be used to upgrade a 386- or 486-based system into a 486 or 586 system.
Various models use special sound cards for backwards compatibility, but apparently NEC screwed up and on some models it doesn't actually work as intended. Speaking of soundcards, some PC98 machines are really impressive, with FM Synth and Roland MIDI boards included by default, even on laptop models (!).

Platform was popular for Touhou games.

PC-9821 only, AFAIK.

Jap. MS-DOS: runs on PC98, has compatibility issues with western software (perhaps a few text-mode programs will work).
Jap. Windows: runs on PC98. Last version was Win98SE (and Win2000). Can also run normal Windows programs from the IBM PC platform.

From Windows 95 onward only, because from that point the access to hardware was handled by Windows instead of the programs. So it's not possible to run a Western DOS-based game that needs to access hardware directly on a PC98 system. Likewise, games and programs for the PC98 that directly access the hardware were designed with the specific hardware limitations of the PC98 system in mind, so they won't run on AT-compatibles because they look for resources that are not there.

DOS/V: Japanese DOS which runs on western IBM/AT class machines (+386, maybe also 286, uses EMM386). Last version by MS was 6.20 […]
Show full quote

DOS/V: Japanese DOS which runs on western IBM/AT class machines (+386, maybe also 286, uses EMM386). Last version by MS was 6.20.
Uses VGA graphics mode to provide Kanji/Katakana characters. Hence the "/V" naming scheme. Also has a western mode (Romanji).
Partially compatible with jap. MS-DOS on PC98, some games have built-in support for both platforms.
A TSR for English DOS, DOSJP, is available to provide limited compatibility with jap. character set.
Apparently, there also was a Korean version of DOS/V. The name "DOS/V" (ドスブイ) is also used as a generic term for any (western) PC.
Win/V: "Win/V" refers to an extension for English Windows (Win 3.1). It was published by Fast River Systems.
Jap. versions for PC98 and DOS/V were sold separately (included different drivers).

AFAIK, DOS/V was sold in a version for Western X86 systems and a version for PC98. The same applies to Windows 3.1, 95, 98, 2000.

Again, that's just a tiny explanation for beginners. Someone could literally write several pages about this matter. 😅
If you find any mistake, you can keep it. Just kidding! I'll be glad if someone has something to add, whatever it is. 😉

Some more stuff: Being a Japanese system, they run on 100V A/C. The video output is specific and requires a special type of monitor, although there are VGA-convertors available. The keyboard connector is also specific, as is the keyboard. Several of the standard ports on the motherboards look like PC-compatible ports, but are not. Early floppy disk drives use specific hardware with controllers on the floppy board itself and sometimes special floppy formats (esp. 5.25" drives). Hard disks were not standard until quite late (mid-1990s) on low-end machines and used SASI, SCSI, or IDE interfaces. An alternative for a hard disk are persistent RAM drives (with a battery on-board) that plug into NEC's proprietary extension ports.

I've also noticed that quite a few resellers sell stripped down second hand systems where all interesting stuff (sound cards, SCSI cards, hard disks, sometimes even floppy disk drives) was removed, with the expansion cards separately listed for obscene prices.

Whoa, thanks a lot! 😁 You know a lot about this stuff. I'm glad for your explanation.

Did you know that DOS/V 5.0 and DOS/V 6.2 do use a different technique for screen scrolling ?
If I did understand correctly, DOS/V 5 uses the CRTC address counter to let the screen wraparound happen by itself.
DOS/V 6.2 on the other hand, does accomplish the same results by creating a split screen.
Perhaps they did change this to fix things on buggy VGA clone cards.
The details can be read here:

DOS/V graphics text modes and scrolling
http://www.os2museum.com/wp/dosv-graphics-tex … -and-scrolling/

In case you're interested I've found a few more links.
They are nothing special, though. Just random stuff from my browser's history.

DOS/V: The Soft(ware) Solution to Hard(ware) Problems
Nice article from the times when DOS/V competed with PC98.

How were PC-98 games such as Rusty and Princess Maker 2 ported to IBM PC(DOS/V)?
Were major coding modifications needed?
..

FreeDOS(98) - FreeDOS for PC8
I'm not sure if it a complete port of FreeDOS for PC98 already, but the FreeCOM interpreter is mentioned.

The Touhou PC-98 Restoration Project ("ReC98")
Touhou on Windows

C-BUS article on Japanese Wikipedia
It seems there also was NESA/E-BUS (an EISE derivative) and 98 local bus (486 VL Bus clone ?).

Qemu & the PC98
As the title says. It's about a special version of QEMU.

MS-DOS Player for Win32-x64
This application runs on the Windows CLI and emulates a DOS-driven 286 machine in text mode.
Useful for running ancient utilities like arc or Clipper on Win64. 😀

Japanese Pc Games (Blog) @ Assemblergames
A thread about WIn/DOS/PC98 games. Lots of box art is shown.

Thread about Japanese EGA (JEGA)
About the early hardware-based kanji PCs.

And last, but not least some nice Vogons threads..

Are PC-98 games compatible with DOSBOX?
Old Japanese Games for PC (DOS/Win9x)
Technically impressive FM synth music
NEC PC8801 / PC9801

By the way, Wikipedia of Japan also mentions these other language versions of DOS/V:

Korean version: IBM DOS H5.0 / V, PC DOS H7
Taiwanese version: IBM DOS T5.0 / V, PC DOS T6.1 / V, PC DOS T7
Chinese version: PC DOS P6.1 / V, PC DOS P7

I think it is alo notable that Digital Research released a DOS/V version of DR-DOS 6.0..
Too bad I can't find any information about it, like its release date.

Jo22 wrote:

Whoa, thanks a lot! 😁 You know a lot about this stuff. I'm glad for your explanation.

No, no, It's just information I've read in the last few weeks as I'm trying to figure out what the possible bottlenecks are if I get a PC-98 system (aside from my very limited knowledge of the Japanese language). I mean, if I can't even get any video output displayed because the monitor needs to support a specific frequency that most Western monitors don't support... (see this Reddit thread).

Did you know that DOS/V 5.0 and DOS/V 6.2 do use a different technique for screen scrolling ? If I did understand correctly, DOS […]
Show full quote

Did you know that DOS/V 5.0 and DOS/V 6.2 do use a different technique for screen scrolling ?
If I did understand correctly, DOS/V 5 uses the CRTC address counter to let the screen wraparound happen by itself.
DOS/V 6.2 on the other hand, does accomplish the same results by creating a split screen.
Perhaps they did change this to fix things on buggy VGA clone cards.
The details can be read here:

DOS/V graphics text modes and scrolling
http://www.os2museum.com/wp/dosv-graphics-tex … -and-scrolling/

I'm not that technical, but another explanation might have been that this was done to facilitate porting software from PC98 to regular x86 architecture before PC98 switched to PCI/AGP videocards.

C-BUS article on Japanese Wikipedia
It seems there also was NESA/E-BUS (an EISE derivative) and 98 local bus (486 VL Bus clone ?).

98 local bus is the successor to C-bus, I think (the riser cards plug into ISA/PCI slots*). There's also a few dedicated busses for specific hardware on later PC-9821 models, for fax boards, MIDI boards, and possibly TV in/out boards (each type of board has its own slot). The proprietary C-bus and 98 local bus (and probably also NESA/E-bus) cards are almost square, with the connector that goes into the bus opposite eventual external connectors, which is why they need to connect to the motherboard using a riser.

Edit: here's an example of a 98 local bus card: http://www.itmedia.co.jp/enterprise/articles/ … /news008_2.html
And a page with more information on NESA: http://www.toride.com/~h98/donna.htm Looks like it is very similar to 98 local bus? But not compatible, if I read the translation of that page well (not that it matters, because NESA seems to have been rather unpopular).

* Actually I should say: the slot the riser card plugs into looks like a PCI or ISA slot on some systems.

If you want to see lots of pictures of hardware and software, go browse the PC98 section of Yahoo Auctions Japan (avoid Ebay, any machine on there is really overpriced). You'll need to use a middleman service and find a seller that wants to sell to such a service to actually buy anything. Also keep in mind that some PC-98 systems are right against the weight limit for parcel mail from Japan (20 or 30 kg, depending on the service used).

Just found this awesome page for anyone who is interested in Japanese computers in general:

IPSJ Computer Museum 😁

yawetaG wrote:

Just found this awesome page for anyone who is interested in Japanese computers in general:

IPSJ Computer Museum 😁

Awesome, thanks! 😁

It has a lot of background information, it seems!

I'll browse through it tonight.

yawetaG wrote:

If you want to see lots of pictures of hardware and software, go browse the PC98 section of Yahoo Auctions Japan (avoid Ebay, any machine on there is really overpriced). You'll need to use a middleman service and find a seller that wants to sell to such a service to actually buy anything. Also keep in mind that some PC-98 systems are right against the weight limit for parcel mail from Japan (20 or 30 kg, depending on the service used).

I realized in the last few days that a lot of the later PC-98 cards and peripherals are not actually listed by "PC-98", but by the name of their manufacturer, card type or external interface type. You need to look at the pictures for clues - fortunately almost everything pre-1998 is for the PC-98 or Macs. Big names are I O Data (or I/O Data or I.O Data) and Buffalo. Lots of SCSI stuff.

Thank you for telling me! 😀
I've also found out that Microsoft and Intel had a "PC 98" specification as part of their PC System Design Guide.
I'm sure this will lead to confusion at beginners evenmore. Funnily, the non-PC98 compatible PC98-NX series
was compliant to this. NEC really had a sense for dark humor. 😉

Hello yawetaG, how is it going?
I have found a few more links for the PC-98 for you..

http://www.pc-98.jp/
http://www.pc-98.net/
http://www.pc-9800.net/
http://www.pc-9821.org/
pc98 org (reviews, translations and images)

The NEC PC-98 - Obsolete Geek
https://www.youtube.com/watch?v=2HDGJE80DWY
http://nfggames.com/forum2/index.php?topic=6045.0

By the way, be careful with the PC98-NX series. These are ordinary IBM compatible PCs in disguise (DOS/V computers).
They can't run any PC-98 software, except those rare dual-platfrom games.
Or Windows games, of course, as they are only depended on the CPU and the Windows API (or OS/2 API when running OS/2).

For details see this page.

Another cool private homepage is this one (translated).
It does also have a timeline of the PC98 family (translated).
The different models are described here (translated).

Oh, and thank you again for the link to the IPSJ Computer Museum.
They do mention another cool Japanese computer type, the Fujitsu FM R Series (Panacom M Series compatible).
Apparently, they also had some kind of MS-DOS 6.0, a 286/386DX and the higher-end models supported a 1120 x 750 graphics mode.
Not bad for machines from '88 (FM R 70)! I heard PC-98 also got DOS 6.0 as "EPSON MS-DOS 6.0".

Thanks for the links.

Jo22 wrote:

By the way, be careful with the PC98-NX series. These are ordinary IBM compatible PCs in disguise (DOS/V computers).
They can't run any PC-98 software, except those rare dual-platfrom games.
Or Windows games, of course, as they are only depended on the CPU and the Windows API (or OS/2 API when running OS/2).

Yeah. Some later machines even use the same naming conventions as the rest of the actual PC-98 lineup, but are ordinary IBM compatibles.
Apparently there also are some issues with different generations of the PC-98 platform itself. Some later machines use graphics cards with zero DOS support (drivers don't exist). Machines that originally came with PC-98 Windows 95 or later can't run DOS games, but systems that had Win95/98 installed over MS-DOS can 😵 , and some systems (CanBe, IIRC) have very high-spec sound and other hardware but don't work in MS-DOS at all. There's also a few specific systems that have a conflict between the PCM and FM sound source functions of the sound card (they can use one or the other, but not both at once). The more industrial NEC product lines sometimes have software-related incompatibilities with the consumer PC-98 systems (which sucks, because they seemed a nice alternative for high-end systems).
NEC, makers of a highly successful country-specific line of computers with very confusing type designations and apparently an inability of keeping systems from the same era compatible with each other... 😒
Regarding the Epson clones, there's at least one laptop system with full compatibility with the actual PC-98 line.

Wow, thanks for all the feedback again. 😀
I just googled, and found a pice of information about these things. I guess you meant the Cirrus graphics with the low DOS support ?
What I heard is that they did at least work with some games, but didn't do the more sophisticated things.
From what I read, that chip in particular could have been the CL-GD5428/5430 (it was built into this laptop).
So I guess this was some kind of modified VGA chip with Windows accelleration ?
I'm surprised this worked at all, because I thought NEC used its own custom chips:

[..] the "GDC" (Graphics Display Controller), an NEC-made graphics chip that had some compatibility with the PC-8x00 series.
Source: https://m.reddit.com/r/pc98/wiki/index/pc-9801

I also found evidences that NEC used these other chips, too (link):
Trident Cyber9320/968x
Matrox Millennium/Mystique
Cirrus 755x
S3 Vision968
NEC EGC, S3 86C775 (Trio64V2/DX)
I wonder, did they also have compatibility issues with PC-98 games ?

PC-9821 / PC-9801 Primer
http://assemblergames.com/l/threads/pc-9821-p … 1-primer.37914/
This one has a buyer's guide and also mentions PC-98 laptops.

Two-dimensional
http://gaming.wikia.com/wiki/Two-dimensional
This one has a timeline about the evolution of 2D graphics chips.
It is also the only source of information I found which mentions the different NEC graphics chips..

Jo22 wrote:

Wow, thanks for all the feedback again. :-) I just googled, and found a pice of information about these things. I guess you mean […]
Show full quote

Wow, thanks for all the feedback again. 😀
I just googled, and found a pice of information about these things. I guess you meant the Cirrus graphics with the low DOS support ?
What I heard is that they did at least work with some games, but didn't do the more sophisticated things.
From what I read, that chip in particular could have been the CL-GD5428/5430 (it was built into this laptop).
So I guess this was some kind of modified VGA chip with Windows accelleration ?
I'm surprised this worked at all, because I thought NEC used its own custom chips:

[..] the "GDC" (Graphics Display Controller), an NEC-made graphics chip that had some compatibility with the PC-8x00 series.
Source: https://m.reddit.com/r/pc98/wiki/index/pc-9801

The Cirrus Logic chips (and others) start to be used when PC-98(21) transitions to Windows 95, AFAIK. The point is that although PC-98 started as an incompatible architecture, it slowly incorporated more and more (approximately) standard PC-compatible hardware as time went on (starting in the early to mid-1990s).
What I find interesting is that the Epson clones didn't, so if they are proper clones it should be possible to get a comparatively faster system that still is mostly compatible with 'classic' PC-98 systems. To clarify, Epson systems with high-end 486 and 586 processors still used C-Bus when the main PC-98 line-up was mostly using ISA and PCI...
Edit: And now that I've read some more about the Epson PC-98-compatible systems, I think I understand why: they have specific settings that can be used for older PC-98 software, including clocking down the processor, a 386 mode, limiting base RAM to 640 Kb, specific video modes, etc. So apparently they were specifically designed to be able to emulate older hardware! Pretty awesome stuff.

I also found evidences that NEC used these other chips, too (link): Trident Cyber9320/968x Matrox Millennium/Mystique Cirrus 755 […]
Show full quote

I also found evidences that NEC used these other chips, too (link):
Trident Cyber9320/968x
Matrox Millennium/Mystique
Cirrus 755x
S3 Vision968
NEC EGC, S3 86C775 (Trio64V2/DX)
I wonder, did they also have compatibility issues with PC-98 games ?

I think it's important to discern between DOS-based and Windows-based PC-98 games. The latter likely work fine. The former may not run if no PC-98 DOS drivers exist for the graphics chip that was used, as many earlier PC-98 DOS games are not actually launched from the hard disk, but from their floppies - so if the game disc doesn't include a compatible driver it won't run.
There appear to be systems that have both the classic NEC chip and a separate Windows accelerator chip though...haven't found much info on those yet other than that the Windows accelerator board is described as "useless" and/or "removable to free a slot required for something else" (guess there was little software that made use of Windows-based graphics acceleration).

I've found something else that's interesting: NEC has a Industrial PC range that is PC-98 compatible named NEC 5200 Model 98. If I understand the translated page correctly, despite NEC suggesting it is using different hardware (slots etc. use different terminology) everything actually is mostly compatible, with the main differences being a boot switch (floppy, HDD, netboot), a differently named-yet-compatible bus (NESA, C-bus compatible, so I guess that makes it the equivalent of EISA), and something involving the boot ROM. Ah, and it has its own operating system: PTOS.
Systems supported by PTOS

Oh, I also found this page with tons of specifications for many Japan-sold systems:

http://www.pc-spec.info/

Missing a lot of information, but it also includes data on what kind of (desktop) software can be run.

This page is interesting for seeing the insides of various systems:
Google translation
There are also subpages that explain how to upgrade the memory of specific systems, how to install FreeBSD, list recommended software utilities, etc.
Oh, and also very useful information for selecting a second hand system (or avoid one):
- Apparently the PC-9821Ce / S1 has built-in SCSI for the CD-ROM drive and hard disk, but will only recognise NEC-branded hard disks. Stick in a C-Bus SCSI adapter to be able to use other makes and the CD-ROM drive stops working - that just sucks 😵
- Many systems use special 61-pin SIMMs. These seem to be the same physical size as regular 72-pin SIMMs, and it's possible to insert the latter in a 61-pin slot (followed by a puff of smoke).

Other stuff:
- The drive numbering works differently compared to Western PCs, so instead of having A: and B: as floppy disk drives, C: as the hard disk, and D: as the CD-ROM you can have the hard disk on A:, floppy disk on B:, and CD-ROM on C:.
- Furthermore, PC-98 has no limitations regarding multi-booting different versions of MS-DOS or Windows! This page lists a system with MS-DOS on partitions A: and B: and Windows 95 on C: and D: (and I guess the FDD is drive E: and CD-ROM F:). It's possible to boot into either system. I already suspected something like that when I saw that some industrial PC-98 systems came triple-booting right out of the box.

yawetaG wrote:

Edit: And now that I've read some more about the Epson PC-98-compatible systems, I think I understand why: they have specific settings that can be used for older PC-98 software, including clocking down the processor, a 386 mode, limiting base RAM to 640 Kb, specific video modes, etc. So apparently they were specifically designed to be able to emulate older hardware! Pretty awesome stuff.

While digging for specs on Epson's non-PC-98 x86 systems, I discovered something very interesting: they sold Intel 486-based and above systems in North America that can be clocked down to 8086 speeds using a similar method as their Japan-only PC-98 compatibles! Better yet, the manuals and specs and sometimes drivers are available on their US site...just go to the support section, click "Browse by product category", then "Other products" and select the appropriate option. Now this is a manufacturer that understands what "legacy support means". 😎

Sounds great! Thanks for the feedback again! I've looked for the manual of a model that has the name of a Space Shuttle.
And yes, I also think that Epson indeed made interestings things in this regard.
This totally reminds me of a specific x86 card, which was also made by Epson.. 😉

But back to the manual again.. The paragraph you meant was this one, I think:

Setting the Processor Speed
The System speed option lets you set the default speed for your system.
When you select Fast, your system operates at your processor’s highest speed,
such as 25,33, or 50 MHz. The Slow option simulates an 8 MHz processor to
provide compatibility with older application programs.

That's cool indeed. 😎 I guess there's also a key combo or a TSR program ?

And regarding the Epson website: It looks nice and tidy (no 404 pages)! Something HP could really learn from.

Yes. There's actually a whole bunch of models that show such options, really worthwhile to read a few manuals. Some of the older systems use dip switches while some later ones use special keys or key combinations.

Also just found these:
- Laptop docking station with expansion bays fora laptop that can be expanded with additional memory and co-processor: https://files.support.epson.com/pdf/nb3exp/nb3exppg.pdf
- Combo 1.44 Mb floppy disk drive & PCMCIA slot, with ISA adapter that comes with or without PCMCIA slot: https://files.support.epson.com/pdf/dyo211/dyo211u1.pdf This is actually a kind of option that is very PC-98-ish, as PCMCIA adapters for desktop systems seem to have been a popular option for the later Windows-based PC-9821 systems. Good to know it was also sold in the western world.

Yay, thanks again. The concept of docking stations was cool. I remember that my Compaq SLT 286 had a similar one (they called it Expansion Base).
It allowed to have two external ISA slots and provided an easy access to all ports.

Wait, here's an old review and a video about it..

Speaking about PCMCIA.. I have to confess that back in the day, I totally missed it. 😅
The laptop we had didn't feature one of these new slots and our 386 desktop didn't have one either.
But looking back, it was really an interesting technology - like a miniature version of ISA.
I remember that it was beeing advertised as an universal slot for both PCs and mobile devices and that
IBM DOS (that's how PC-DOS was called for some time after 3.x) made a big fuss about supporting it.
Same for OS/2 v4 - it was very proud of its good PCMCIA support! And let's don't forget about the Amigas.
Their later lower-end models (A600/1200 ?) -which where essentially based around laptop-style hardware- also supported PCMCIA and IDE.
PCMCIA (ISA) was later named PC Card (ISA/PCI) and finally evolved into Express Card (PCIe).

I've also found two interesting videos for you, covering PCMCIA!
https://www.youtube.com/watch?v=cosUxaI5nSw
https://www.youtube.com/watch?v=8gcnMTi5K_s

And here's another one. It isn't related to PCMCIA, though, but building a normal and generic 386 PC (DOS/V machine).
Still quite entertaining, I think. The person in the beginning recommends a Hercules video card. 😉
https://www.youtube.com/watch?v=J5_doCwi608

Edit: Wait, here's also a picture of my PCMCIA to ISA card. Luckily, these types of cards were made (albeit less common in our place).
Thanks to them, it is possible to use more modern devices like GPS receivers or wi-fi cards in oldskool portables and desktop PCs.

Jo22 wrote:

PCMCIA (ISA) was later named PC Card (ISA/PCI) and finally evolved into Express Card (PCIe).

PCMCIA is an extension of the ISA bus but without DMA support, it evolved into CardBus (32-bit PCI).

Ah sorry, thank you. I meant that card slots were both 16/32bit by the time it was known as PC Card.
I really should have been more precise. 😅
Here's a more accurate definition I've found at Wikipedia :

PC Card = PCMCIA Card (older name): 16-bit or 32-bit
PC Card 32-bit version = Cardbus (alternative name)
16-bit vs. 32-bit: 32 bit includes DMA or bus mastering, 16-bit does not
Types I–III:
Type I: 16-bit. Configuration thickness 3.3 mm
Type II: 16-bit or 32-bit. Configuration thickness 5.0 mm
Type III: 16-bit or 32-bit. Configuration thickness 10.5 mm
PC Card was superseded by ExpressCard in 2003.

Fun fact - It seems the popluar Compact Flash standard was derived from PCMCIA, too.
Guess that's why there were so many CF to PCMCIA adapters around back in the 90s. ^^
"The CompactFlash interface is a 50-pin subset of the 68-pin PCMCIA connector"
https://en.wikipedia.org/wiki/CompactFlash

Also, the japanese JEIDA standard and PCMCIA finally merged in '91.
There's an interesting versions history about that on Wikipedia.
Since this is a PC-98 tread, I couldn't resist to point it out : 😀
https://en.wikipedia.org/wiki/JEIDA_memory_card

Oh wow, just found this awesome page (lots of info there):

http://radioc.web.fc2.com/ (some of the subpages are in English)