Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!apple!motcsd!udc!radium.urbana.mcd.mot.com!dfields From: dfields@radium.urbana.mcd.mot.com (David Fields) Newsgroups: comp.arch Subject: Re: Be Prepared... Message-ID: <2457@urbana.mcd.mot.com> Date: 28 Feb 91 16:32:05 GMT References: <7517@uceng.UC.EDU> <12064@pt.cs.cmu.edu> Sender: netnews@urbana.mcd.mot.com Reply-To: dfields@urbana.mcd.mot.com Lines: 24 |>glew> The NP1 UNIX team used a lot of those ideas for using cheap |>glew> memory. |> |>Like 32KB pages that are a win only if you do numerical calculations in |>the same memory order as the matrix is stored, so that you have less TLB |>reloads, for a speed up of maybe 5%, and in all other cases *waste* |>50-80% of memory? :-). |> |>Let's distinguish between ideas for *using* cheap memory and ideas for |>*productively using* cheap memory. And let's distinguish between |>programs with hardwired assumptions and flexible programs. |>-- |>Piercarlo Grandi Sorry, the NP1 used 8k pages. I was only on the periphery of the project and while I don't think any of the developers were satisified with the amount of memory used or wasted it wasn't any where near the 50-80% you jest. If I believed there was a target market for the NP1 I might try to defend the design decisions but .... It was fast for the time, however, and it held up very well with very heavy multi-user loads. Dave Fields // Motorola Computer Group // dfields@urbana.mcd.mot.com