3 ms·
Keep in mind that although the Alto disk is removable, it is a hard disk, not a floppy; the user normally kept it mounted for a session, rather than using a new
by kens 10y ago
Keep in mind that although the Alto disk is removable, it is a hard disk, not a floppy; the user normally kept it mounted for a session, rather than using a new disk every time they load something. Thus, the disk needs to hold everything you need. (Although you could access files over the network with FTP.)
The user guide describes in great detail [1] why Alto users found 2.5MB of disk limiting. To summarize, the disk starts with 4800 512-byte pages. Basic OS stuff takes 900 pages. FTP and the editor take 900 pages. Fonts take more, as well as other commonly-needed software. So a non-programmer's disk typically has 1600 pages (800kB) available to work with. Programmers require more tools, so the free disk space is tighter. It seems people ended up needing to manage their disk space closely, even though 2.5MB sounds like a lot.
[1] See pdf page 20 of http://bitsavers.org/pdf/xerox/alto/stanford/StanfordAltoUsersGuideSep80.pdf http://bitsavers.org/pdf/xerox/alto/stanford/StanfordAltoUse... for a discussion of why disk space on the Alto was rapidly used up.
- e12e 10y agoI see. That coupled with the limited RAM (as opposed to eg: the Amiga 500 which had 512Kb), or the Amiga 2000 which had at least a full megabyte -- I think ours had 4MB does make a big difference. Interesting to note (as @pjmlp mentions) that 1973 + 15 years leaves us at around the time the Amiga 2000 was introduced. I remember ours (a model b IIRC) initially had a 20MB hard-drive, later upgraded with another 40MB for a total of 60MB of storage. It could fit almost all of my floppies on there! Looking at the wikipedia page for the Amiga 500 I see the RAM latency listed as 150 ns. I'm not sure if that's the actual latency to read data from RAM - if so it's within an order of magnitude for accessing RAM today! (I'm also a little sad that while my i7 is a lot faster than that ageing 68000 that ran at 7.5 Mhz, it's still not easy to find a single core with 7.5+ Ghz of performance :-( ...).