Path: ns-mx!uunet!jarthur!usc!wuarchive!cs.utexas.edu!asuvax!noao!rutgers!att!cbnewsd!dcn From: dcn@cbnewsd.ATT.COM (david.c.newkirk) Newsgroups: alt.folklore.computers Subject: How Virtual Memory Really Works (or Doesn't Work...) Keywords: I/O Deja Vu from old Creative Computing Message-ID: <14498@cbnewsd.ATT.COM> Date: 4 May 90 14:06:04 GMT Organization: AT&T Bell Laboratories Lines: 71 The recent posting about the Thing King reminded me of a similar parody in an old Creative Computing magazine - enjoy! I/O Deja Vu - A Farce in One Act -------------------------------- IBOX: Hello, CACHE? I'd like the data for location 54321. CACHE: I'm sorry sir. I don't have that data. Just a moment and I'll try to get it for you. CACHE: Hello, MAP? I need the address for location 54321. MAP: I don't have that address, sir. That address is stored at location 76543. Just a moment and I'll try to get it for you. Hello, I/O control? I need the data from location 76543. I/O: Just a moment. I'll try to get it. Hello, CACHE? I need the data from location 76543. CACHE: I don't seem to have that data, and I'm not about to get it. I/O: Hello, MAP? What is the address for location 76543? MAP: That address is 222543. I/O: Hello, CORE? What is the data at 222543? CORE: That data is INDIRECT PAGE TABLE 21, PAGE 44. I/O: Hello, MAP? That data you wanted is INDIRECT PAGE TABLE 21, PAGE 44. MAP: Fine. Now I need INDIRECT PAGE TABLE ENTRY 21. That would be stored at location 556. Would you get me the data at 556? I/O: I'll try. Hello, CACHE? I need the data from location 556. CACHE: That data is 6767. I/O: Hello, MAP? That data you wanted is 6767. MAP: Good. Now, let's see. 6767 plus 44 is 7033. Now, get me the data at 7033. I/O: Hold on. Hello, CACHE? I need the data from location 7033. CACHE: I'm sorry. I don't have that data. You'll have to get it from CORE. I/O: Hello, MAP? I need the address for location 7033. MAP: I'm sorry. I don't seem to have that address. I'll try to get it, but I'll probably forget what I was doing before, so you might as well too. MAP: Hello, I/O? I'm trying to get the address for 7033. That data should be stored at location 112233. Would you try to get me that data? I/O: (sigh) I'll try. Hello, CACHE? I need the data from location 112233. CACHE: That data is 4242. I/O: Hello, MAP? That data you wanted is 4242. MAP: I'll store that away. HEY IBOX, I just stored something. IBOX: Hello, CACHE? I'd like the data for location 54321. CACHE: I'm sorry sir. I don't have that data. Just a moment and I'll try... -- Dave Newkirk, att!ihlpm!dcn