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Conference hydra::amiga_v1

Title:	AMIGA NOTES
Notice:	Join us in the NEW conference - HYDRA::AMIGA_V2
Moderator:	HYDRA::MOORE

Created:	Sat Apr 26 1986
Last Modified:	Wed Feb 05 1992
Last Successful Update:	Fri Jun 06 1997
Number of topics:	5378
Total number of notes:	38326

273.0. "Memory expansion questions" by ECC::JAERVINEN (impersonal name) Mon Jan 26 1987 10:15

    Still a non-owner - and more questions:
    
    The Amiga sells here with 512k memory built in - and, obviously,
    you can get various memory expansion boards.
    
    The question is: what would happen if you plug in one of the
    old 256k upgrades into the slot (is that the one in the front?)?
    Or is that kind of memory limited to 512kb (chip memory, whatever
    that is)? (The old 256k upgrades are dirt cheap now...).
    
    Or can memory chips be piggybacked to the internal ones? I've
    seen one article that explained how to do this for the 256k version.
    (Not that I really like that kind of work... just asking).

T.R	Title	User	Personal Name	Date	Lines
273.1	...	LEDS::ACCIARDI		`Mon Jan 26 1987 12:35`	35
	The removable 256K card that plugs into the front of the machine has ordinary 256K x 1 RAM chips in it. That card does not interface with the 68000 expansion buss. The lines that run from the front slot are only available to CHIP ram. The lines that run from the edge buss are only available to FAST ram. The internal memory upgrades that people are doing cause memory to be added to a 'hidden' area, space that would have been available to the 'FAT AGNES' chip, which can address 2 megs directly rather than 512K. If one did nothing but install the piggyback chips, the Amiga would try to configure the extra ram as CHIP, which the custom chips cannot recognize. So, some hardware (a PAL, I believe) has to be added to force the memory to be configured as FAST ram. By the way, the piggyback upgrade can also be performed on the front 256K card, but you must jumper over to the motherboard anyway. The latest issue of Amazing Computing has an article about doing the upgrade, with photos and step by step instructions. I can copy the article for anyone who wishes to see it. By far the easiest fix is to go buy an Allegra or Microbotics RAM board. The Microbotics 2 meg can be bought for $525.00 mail order. And you don't have to void your warranty or touch a soldering iron. I hope I understood your question correctly. Over here, Amigas have only 256K total until you add the front 256K card. It could be that dealers are performing an internal upgrade to 512K. If that is the case, then added the front card would not increase CHIP or FAST memory. However, with the 256K front card selling for $79.00, I doubt that anyone would bother to open the machine to piggyback an extra 256K. Another possibility is that dealers ARE doing a 256K piggyback, adding the autoconfiguration hardware, and ending up with 512K CHIP ram and 256K extra FAST ram.
273.2		ECC::JAERVINEN	impersonal name	`Tue Jan 27 1987 03:22`	7
	Thanks for the info. The Amiga is really delivered with 512k here, always, straight from the factory. In the first few months they sold 256k US versions, that's why thos 256 upgrades are still available. (The 512 is a PAL (as vs. NTSC) version with a German keaboard).