I was totally blown away by the design of the apple II wehn it came out. I used to design my own computers and sell other computers (like the SOL ) mentioned in the story.
The dynamic memeory trick was the key to the future of computing. At the time all computers used static ram. You could buy memory cards with dynamic ram but the refresh on all of these things was unstable. The main problem was that you had to periocally stop the cpu and raste through part or all of the memory to induce a refresh. With the intel CPU's this was rough. their timeing cycles varried form instruction to instruction, plus you had to deal with unfreindly I/O devices holding down the WAIT line on the s-100 bus where the memory was.
Woz finessed this with two beautiful tricks. first they used the 6502 cpu which had a steady instruction rhythm compared to the intel. You could always count on the memory bus being unused on the back side of every clock cycle. This eliminated the uncertainty of when you could reach the memory to refresh it. second they used the video scan as the refresh it self. since the video memory was in main memory, any access to the video also refresed all of the memory locations with the same upper address byte. beautiful, gaurentted refresh and no extra circuitry to do it. zen like perfection.
Other cool features were memory mapping not only the I/O but also mapping the plug-in cards to pre-decoded memory. The floppy disks were soft sectored rather than hardware timed. the net effect of the memeory mapping and soft sectoring was that the software could replace hardware. At the time this made for inexpensive yet flexible computers that could do things you would not have been able to think of in hardware. For example, game "sprites" which where like icons that move. think Mario bros and you got it. since the video was memory mapped you could just move these little tile icons around. CGI type devices had a huge handshaking hardware driven overhead and you could not just do a DMA meemory move of one section of screen memory to another.
apple has been at the center of civilizing innovative products that were not being perceived for their true nature. Often new products are seen as just a new way of doing something old. But apple has consistently seen the radicallizing nature of things. dynamic memeory was just one example. Another was the use of a switching powersupply. these were tiny power supplies. but until the apple computers were either tiny (like the trs-80) and had no upgradability or had huge cards like the S-100 bus intel machines and so having a HUGE conventional transformer power supply dominated the interior of the box. The aple II was svelt yet had lots of power for it's cards. The memory mapped cards meant fewer hardware hancshing chips on the cards and thus they could be smaller too.
Adoption Post script for laser printers was another. At the time laser printers like the HP laerprinter worked just like impact printers or screen graphics. you could only print in a slected hardwired font and pitch. You could print individual pixels but there was no way to really do creative high level graphics. post script changed all that and now we take it for granted. When NeXT came out they percieved how massive disks were needed for software distrubution as well as for images and sound. at the time a 10 Megabyte hard drive seemed unfillable. But NeXT shipped with optical drives which could hold as much as a CD. Of course this turned out to be a bad decision because the need for large drives lagged and the optical drives were very slow comared to harddrives. They were too far ahead of us in realizing how we were going to be using out computers.
and of course one could wax rasphodically about the macintosh
Size problems I've run into with Apple Software Restore (4GB limit) and Rsych (appears to have either a file count limit or a directory tree depth limit) are concerns. Can you say if this new rsynch has removed this limit, or if psynch has it?
Wow. you sure read my mind on the question about forks. I'm setting up my first raid Xserve (jaguar) and am trying to figure how much to partition where and whther to UFS or HFS it...
it's going to serve a giant pentium linux cluster of scientific compute nodes. But I will probably also use it as sort of a storage depot for my apple laptops. might even serve my mail and local web off it too.
I sure would like to be able to ask you some questions, if you dont mind. If your willing my e-mail is delete the capitals in ceNOms@iSwPAMon.com
You have to be careful on macs in my experinece. simply copying all you mac files to another unix file system can sometimes loose the extra stuff in mac files like resource forks and creator codes. I'm not an expert on this, but macs have the unix command "ditto" (see man ditto) which is like 'cp' but takes care of that extra stuff. I dont know what rsynch would do.
The problem I've had with rsynch is that it seems to have a file tree size limit at which is spits up and fails. I dont know how to work around this. Yes I do do evil things like have 20,000 files in my direcories, but I have sound reasons for doing so not shear lazyness.
Anybody know how to fix this
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The dynamic memeory trick was the key to the future of computing. At the time all computers used static ram. You could buy memory cards with dynamic ram but the refresh on all of these things was unstable. The main problem was that you had to periocally stop the cpu and raste through part or all of the memory to induce a refresh. With the intel CPU's this was rough. their timeing cycles varried form instruction to instruction, plus you had to deal with unfreindly I/O devices holding down the WAIT line on the s-100 bus where the memory was.
Woz finessed this with two beautiful tricks. first they used the 6502 cpu which had a steady instruction rhythm compared to the intel. You could always count on the memory bus being unused on the back side of every clock cycle. This eliminated the uncertainty of when you could reach the memory to refresh it. second they used the video scan as the refresh it self. since the video memory was in main memory, any access to the video also refresed all of the memory locations with the same upper address byte. beautiful, gaurentted refresh and no extra circuitry to do it. zen like perfection.
Other cool features were memory mapping not only the I/O but also mapping the plug-in cards to pre-decoded memory. The floppy disks were soft sectored rather than hardware timed. the net effect of the memeory mapping and soft sectoring was that the software could replace hardware. At the time this made for inexpensive yet flexible computers that could do things you would not have been able to think of in hardware. For example, game "sprites" which where like icons that move. think Mario bros and you got it. since the video was memory mapped you could just move these little tile icons around. CGI type devices had a huge handshaking hardware driven overhead and you could not just do a DMA meemory move of one section of screen memory to another.
apple has been at the center of civilizing innovative products that were not being perceived for their true nature. Often new products are seen as just a new way of doing something old. But apple has consistently seen the radicallizing nature of things. dynamic memeory was just one example. Another was the use of a switching powersupply. these were tiny power supplies. but until the apple computers were either tiny (like the trs-80) and had no upgradability or had huge cards like the S-100 bus intel machines and so having a HUGE conventional transformer power supply dominated the interior of the box. The aple II was svelt yet had lots of power for it's cards. The memory mapped cards meant fewer hardware hancshing chips on the cards and thus they could be smaller too.
Adoption Post script for laser printers was another. At the time laser printers like the HP laerprinter worked just like impact printers or screen graphics. you could only print in a slected hardwired font and pitch. You could print individual pixels but there was no way to really do creative high level graphics. post script changed all that and now we take it for granted. When NeXT came out they percieved how massive disks were needed for software distrubution as well as for images and sound. at the time a 10 Megabyte hard drive seemed unfillable. But NeXT shipped with optical drives which could hold as much as a CD. Of course this turned out to be a bad decision because the need for large drives lagged and the optical drives were very slow comared to harddrives. They were too far ahead of us in realizing how we were going to be using out computers.
and of course one could wax rasphodically about the macintosh
Size problems I've run into with Apple Software Restore (4GB limit) and Rsych (appears to have either a file count limit or a directory tree depth limit) are concerns. Can you say if this new rsynch has removed this limit, or if psynch has it?
it's going to serve a giant pentium linux cluster of scientific compute nodes. But I will probably also use it as sort of a storage depot for my apple laptops. might even serve my mail and local web off it too.
I sure would like to be able to ask you some questions, if you dont mind. If your willing my e-mail is delete the capitals in ceNOms@iSwPAMon.com
You have to be careful on macs in my experinece. simply copying all you mac files to another unix file system can sometimes loose the extra stuff in mac files like resource forks and creator codes. I'm not an expert on this, but macs have the unix command "ditto" (see man ditto) which is like 'cp' but takes care of that extra stuff. I dont know what rsynch would do.
The problem I've had with rsynch is that it seems to have a file tree size limit at which is spits up and fails. I dont know how to work around this. Yes I do do evil things like have 20,000 files in my direcories, but I have sound reasons for doing so not shear lazyness. Anybody know how to fix this