Notes

Details: Published: 01 May 2025

N33 is derided from the 8533 Model Type. Yeah, IBM had some really snappy titles back before the Thinkpad.

Note: this article is about the 12Mhz 386 model which was seemingly derived from the first generation PS/55 Note, whereas the 16Mhz version was derived from the second generation PS/55 Note which was called the N23 SX. Inside it's a completely different motherboard to the 16Mhz with no external display, no invert display switch and no built in floppy because the two-part construction of the main two boards leave no room for the Hard Drive to mount on top of them - therefore it's moved to take up the space of the floppy drive. I believe it was an option to have either a HDD or a FDD and my one has the HDD option with FDD connected via the external connector.

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IBM 5535 Multistation

IBM Japan had a range of Kanji-character-enabled desktop computers, called the Multistations. This was part of that family with the addition of a greyscale LCD display. Although 5535 is the 'laptop' range of machines, With the sheer size and weight (7kg), I think you would consider it more like a 'space saving desktop', much like the IBM Convertible. It has a sibling called the 5535-S which has a slightly different design and is 'less boxy'.

IBM PS/2 Model CL57 SX

This is a massive, stange, outlier in IBM's journey into portable personal computers. CL for 'Color Laptop' and 57 for....... fuck knows. The type is 8554 and it runs MCA bus. It's almost completely unique although it shares a look similar to that of the possibly-vaporware, Japan-only PS/55 Power (PC) Laptop EWS - which also feels like a skunkworks project.

Some sources state this machine started as a Model N27sx - a 'for fun' IBM Japan design for domestic japanese market. I can't find much source material that this is true though. Apparently, the CPU was downgraded from a 486 to a 386 so as to not compete with other PS/2 machines. Supposedly there are some hidden clues on the machines that despite it's international 85xx model designation, the plant ID is 97 which is IBM Japan Entry Systems factory in Fujisawa.

PS/55 Note N51 SX and SLC

After the successes of the original note (1st Gen), the N23 (2nd Gen) and the N33 machines, two machines share the third generation space - the still-monochome MCA N51 and TFT Colour, ISA C23V.

Notes on notes

Note: The 5499 On-Line note isn't really part of the brand note family. Whilst it's certainly a notebook, it's a weird dead end portable terminal which has very little use unconnected to a maintrame.

PS/55 note - The PS/55 was a range of Type-55xx computers for only Japan. They're based on the PS/2 but ISA bus and with special Japanese localisations supporting the more technically difficult languge to display on screen and type on a keyboard.

The 'note' branding was devised for the Notebook versions and within Japan all had to be in the 5523 model range (as opposed to 5535 for laptops). The original (or 1st Generation) 12Mhz PS/55 Note was the 386 5523-S0x model with sandwiched planars and room for either a FDD or HDD.

765D

Here are some notes on my 765D. The 765D was a halfway house between the tilting keyboard 760 and the larger-screened 770.

PS/Note N33 SX Type 8533 (12Mhz)

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