Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!sequent!talon.UCS.ORST.EDU!cs.umn.edu!kksys!edgar!orac!bret From: bret@orac.UUCP (Bret Indrelee) Newsgroups: comp.sys.amiga.advocacy Subject: Re: The Amiga's Future Summary: Mac O.S. Message-ID: <376@orac.UUCP> Date: 13 Jun 91 02:31:20 GMT References: <1991Jun10.151040.28541@mintaka.lcs.mit.edu> Organization: Technix Inc., Saint Paul MN, USA Lines: 45 In article mykes@amiga0.SF-Bay.ORG (Mike Schwartz) writes: >Pardon me while I whipe the spittle from my face :) Ever notice that the >C128 and the original Mac were pretty similar? Both were slow computers with >slow floppy drives and 128K of RAM. The Mac traded color for resolution... >(It also came with a "real" OS :). > The MacIntosh has a "real O.S."? I though O.S. stood for operating system... the MacIntosh came out with a 'Toolbox' where you were required to develop applications on the Lisa and cross load them. The MacIntosh uses 'A-line' traps for all its functions. It originally had a flat file system rather than the current HFS. I really think that you are streching the definition of O.S. when you say Finder is one. On another tangent, why has no one mentioned one of the biggest reasons that the MacIntosh is so slow? On the MacIntosh, all data is referenced via a handle. This is a pointer to a pointer. After making a toolbox call that allocates storage space, it is neccessary to re-load from the original handle because a garbage collection may have occurred. Since the minimum processor is a 68000, you can't even use the 68020 addressing modes that can automatically do this indirection. Two memory accesses to access data means the MacIntosh has to run the bus and processor faster than other 680x0 systems just in order to keep up. More specific to Amiga, the MacIntosh O.S. uses 'A-line traps' to implement all the Finder calls. Last time I counted (it has been awhile though...) it took at least 20 cycles to execute the exception and decode what routine you wanted to execute. Please compare with the time for a JMP instruction, like would be used for Amiga calling the libraries. -Bret -- ------------------------------------------------------------------------------ Bret Indrelee | Our mail is still somewhat unreliable. Sorry. uunet.uu.net!cs.umn.edu!kksys!edgar!orac!bret -And still trying