dbscoop2@bwdlh417.BNR.CA (Alun Fryer) (04/19/91)
There are at least 5 different Agnuses (Agni?) that I know of. The first is the "normal" agnus, which is a standard DIP chip and only came in the old A1000's. I'm not sure of the part no of it. Then came the "FAT" agnus, which has a part number "8370" (I beleive). There are two of these. One is for NTSC (8370) and on is PAL (not sure of part no.). Then came the (SUPER | ONE-MEG | OBESE | FATTER | REALLY BIG | OH-WOW-I-NOW-HAVE-A-WHOLE-1-MEG-OF-CHIP-RAM ) agnus (pt. no. 8372). This is that same chip for both NTSC and PAL. Finally comes the SUPER_GODLY 2 meg agnus which is only avaiable in the A3000/3000T. (pt. No. - I don't know). I'm not 100% sure of the chip numbers but I do know the old Fat agnus ends in a "0" and the 1 meg ends in a "2". Now as to the question about "why 2 types of RAM?"... The Amiga has 2 types of RAM: CHIP ram and FAST RAM. CHIP RAM is so called since it is the RAM which is accessable by the CUSTOM chips (Agnus, Denise, Paula). The limiting factor is the AGNUS chip. The old FAT agnus would only allow 512k to be "CHIP" ram, where the Newer Super Agnus allows 1 Meg. The A3000 agnus allows 2 Meg. FAST RAM is all RAM which is not CHIP RAM. It is called FAST RAM because the CPU has faster access to it. Well, really what I mean is that since the custom chips don't have access, the CPU doesn't have to wait for them to gain access to the RAM. There is also so-called "SLOW-FAST" RAM which is the second 512k in a machine with a 512k Agnus in it, but I wouldn't worry about it. Basically, CHIP RAM is the only RAM which you can directly use for graphics and sound. If you want more than that (e.g. a 2MB sound sample), your software has to swap the data into CHIP RAM when it is needed. I hope this clears things up a bit. - Alun Fryer
dtiberio@eeserv1.ic.sunysb.edu (David Tiberio) (04/20/91)
In article <1991Apr17.082037.27978@cs.uow.edu.au> u9050728@cs.uow.edu.au (Shane Kelvin Richards) writes: > > Hi, I am a new Amiga Owner. I have the latest Amiga 2000 with 1meg >of chip ram. A couple of things people may be able to clarify for me. Firstly, >how many different Agnus chip versions are they, what is there names and what >is the differences between the models. There are probably 4 versions. I think the model numbers are 8370, 8371, 8372, and 8372a. Agnus - A1000, 512k chip Fat Agnus 8370 - A500, A2000, 512k chip, NTSC Fat Agnus 8371 - A500, A2000, 512k chip, PAL Fatter Agnus 8372 - A2000, maybe A500,1 meg chip, NTSC, PAL Super Agnus - A3000,2 meg chip, NTSC, PAL I have also heard of Obese Agnus, and the MegaChip. > Secondly, I don't understand why there is 2 pieces of ram, fast and >chip. Why have 2? What is the differences? I have 1 meg of chip ram, how is >this going to affect me? > chip ram - needed to run more applications, larger screen graphics/colors, larger sound bytes, directly accesible by custom chips slow/fast ram - seems to be due to A500 hardware in the internal slot fast ram - 4 times faster than chip ram You can alter ram configurations with FastMemFirst, Addbuffers, and from the BuffMemType of the devs:mountlist. > Can people please EMAIL me if they can help. Thanks. Okay, I will EMAIL too! > >-- >+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- >Shane Richards >u9050728@cs.uow.edu.au >+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- -- David Tiberio SUNY Stony Brook 2-3481 AMIGA DDD-MEN Tomas Arce Any students from SUNY Oswego? Please let me know! :) Un ragazzo di Casalbordino, Italia.
daveh@cbmvax.commodore.com (Dave Haynie) (04/24/91)
In article <1991Apr20.014603.21783@sbcs.sunysb.edu> dtiberio@eeserv1.ic.sunysb.edu (David Tiberio) writes: >In article <1991Apr17.082037.27978@cs.uow.edu.au> u9050728@cs.uow.edu.au (Shane Kelvin Richards) writes: >> Hi, I am a new Amiga Owner. I have the latest Amiga 2000 with 1meg >>of chip ram. A couple of things people may be able to clarify for me. Firstly, >>how many different Agnus chip versions are they, what is there names and what >>is the differences between the models. > There are probably 4 versions. I think the model numbers are 8370, 8371, >8372, and 8372a. > Agnus - A1000, 512k chip > Fat Agnus 8370 - A500, A2000, 512k chip, NTSC > Fat Agnus 8371 - A500, A2000, 512k chip, PAL > Fatter Agnus 8372 - A2000, maybe A500,1 meg chip, NTSC, PAL > Super Agnus - A3000,2 meg chip, NTSC, PAL > I have also heard of Obese Agnus, and the MegaChip. Close, but no guitar. There are two "thin" Agnus chips, the PAL and NTSC versions for the A1000. All others are "Fat", though some people like to call them "Fatter", "Super", "Amazing", "Wacky", "Obese", whatever, they're all really "Fat". There are two major varieties of Fat Agnus: non-ECS (also called 512K) and ECS. There are two subtypes of 512K Agnus: PAL (8371) and NTSC (8370). There is really only one ECS Agnus die, but it has two bonding options: ECS 1Meg Agnus (8732A) and ECS 2Meg Agnus (8732B). All ECS Agnus chips do either PAL or NTSC. The 8732A bonding option is pin compatible with the 512K Agnus found in A500s and A2000bs, and has been used in all A2000s for about a year and a half. The 8732B is used in the A3000. > slow/fast ram - seems to be due to A500 hardware in the internal slot The "not really fast" fast RAM is found on the A500 and old A2000s. The deal here is, the original Fat Agnus could support management of 1Meg of Chip memory in hardware, but its internals couldn't deal with more than 512K of RAM. Since we wanted the hardware to be in place to support 1Meg of real Chip RAM when ECS Agnus became available, we built A500s and A2000s with support for 1Meg of RAM on the Chip bus. But only 1/2 of it could really be Chip RAM with the 512K Agnus. So this memory gets located outside of the normal Chip RAM locations, and the system software adds it as Fast, for lack of something better to do with it. It's certainly not Chip, but since it's subject to the same Chip bus activity that real Chip RAM is subject to, it slows down just like Chip RAM. Until you add an ECS Agnus and configure it all as real Chip RAM. Get it? > fast ram - 4 times faster than chip ram Incorrect. Under a normal WorkBench setup, Fast and Chip are essentially the same speed in an A2000 or A500 (with Fast RAM, of course). However, as you add non-CPU load to the Chip bus, via lots of Blitter activity or bitplane fetch, some cycles normally available to the CPU are now devoted to Chip activity, and as a result, Chip RAM gets much slower, from the CPU's viewpoint, than Fast RAM (which never slows down). Under heavy loads, Chip RAM can get much more than 4x slower than Fast RAM, but under a normal Workbench load, as I mentioned, it's basically the same as 16 bit Fast RAM. Once you get to 32 bit systems, you can have Fast RAM that's many times faster than Chip RAM at its best. A3000 Fast RAM, for example, is roughly ten times faster than your basic A500 Chip RAM, at it's best. > David Tiberio SUNY Stony Brook 2-3481 AMIGA DDD-MEN Tomas Arce -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.