Talk:NEAT chipset

Notability

Hello!

I translated the german article for the english Wikipedia, but I am not an expert. I am aware of the fact that sources are missing, but I am sure there are experts out there somewhere. Maybe someone has/had such a board and has a manual or something, or there is a book about the 286 mentioning the NEAT chipset by C&T.

Anyway, considering the (not verified) fact that, “The chipset introduced mainboard configuration via the BIOS which superseded the configuration with jumpers.” makes the “New Enhanced” IBM-PC/AT the first chipset to implement this feature. So, from my point of view, there is no question about notability of the article, althou it might look like a stub in its present state.

What I do know is that some extended memory manager software mentions the NEAT chipset enhancements for the 286 because it made a difference to the memory management of the EMM386 extension (or was it HIMEM.SYS only?). The NEAT-80286 was able to use high memory (640kb-1MB) in a better way (due to bank-switching), whereas the regular 286 had additional limitations.

See for example (search for "NEAT"): [1] or [2]

For what it's worth, ‣Andreas•⚖ 22:19, 12 November 2008 (UTC)

I remember QuarterDeck QRAM using this chipset for special QEMM386 like functions. 76.66.196.229 (talk) 06:12, 19 February 2009 (UTC)

The NEAT chipset was for 286 processors, (Q)EMM386 (that provides EMS) was for 386, hence its name. :-D

AFAIK the NEAT chipset had the feature to remap the 384 KiB of physical RAM, that would be at addresses between A'0000_hex and F'FFFF_hex, beyond the 1-MiB barrier at the addresses 10'0000_hex … 1F'FFFF_hex. At these addresses the RAM is still inaccessible in Real Mode, but it is accessible in Protected Mode (used by OS/2 and Win3.x in standard mode).

But for or DOS and its Real Mode programs there existed memory manager (like HIMEM.SYS in MS DOS) that give DOS programs a special interface to the RAM beyond the 1 Mib barrier: XMS.

It is nearly the same feature that my modern AMD Athlon chipset offers: If 4 GiB RAM are installed (as on my home PC) the chipset maps some RAM from inaccessible address ranges below the 4-GiB barrier to the addresses 1'0000'0000_hex … 1'1FFF'FFFF_hex, as I've seen in /proc/iomem on my Linux 2.6 x86_64 box. :-)

--RokerHRO (talk) 00:06, 29 March 2011 (UTC)

You can download such historical drivers and programs from http://ibm-pc.org/drivers/memory/memory.htm and read through the application notes. I remember owning a 286-NEAT that we'd bought deliberately so we could use utilities like QRAM to move TSRs above the 640K limit, which was rather impressive at the time as a way to gain enough working memory for the then-latest software. A 386 was very expensive in contrast, and a 386SX still that bit too pricey. — Preceding unsigned comment added by 79.255.122.193 (talk) 17:06, 28 April 2013 (UTC)

8085 and peripherals are NMOS ICs, not TTL

TTL refers to a bipolar transistor logic technology. The specific peripherals of the 8085 CPU were made using the same technology than the CPU itself, which is NMOS transistor based, not bipolar.

   the 8284 clock generator[2]
   the 8288 bus controller[2]
   the 8254 Programmable Interval Timer[2]
   the 8255 parallel I/O interface[2]
   the 8259 Programmable Interrupt Controller[2]
   the 8237 DMA controller[2]
   .. and so on

Simple descrete TTL ICs were used in the original XT/AT in addition to these as 'glue' logic. This aspect is wrong represented here. — Preceding unsigned comment added by 87.176.148.236 (talk) 14:26, 30 May 2015 (UTC)