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Disk Drives Explained
CowboyRobot writes "Magnetic disk drives are one of those things I usually take for granted without thinking about, but I recently realized how little I understood about how they really work. ACM Queue has an article from their 'Storage' issue titled, 'You Don't Know Jack About Disks', which does a very good job of explaining exactly how magnetic disks have evolved since the 70s and how they work today."
That's simple; "What computer were you planning on buying?"
I don't know your experience, though this is mine;
I've put computers together for people, I've given them advice, I've even given them a store plus model name plus a few suggestions. I've warned people off of buying a brand, and told them that there are problems with specific hardware that they have thier eye on. All good stuff...none of it aimed toward an agenda...all focusing on what they said they want to do with a specific budget...and they always end up buying what they wanted in the first place or (if I put it together) drooling over the machine they really wanted.
There is no other answer. Unfortunately, the same thing often applies in business though if the managers have good computers they tend to ignore what you do with the rest of the systems.
A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
It always intresting to see how things work. Nice little thing to add to this is the way Nintendo do copy protection on their disks (although not scritly on topic). Instead of relying on heavy software encryption they went for a nice simple solution. They spin the CD-Rom the wrong way. As such you need special burners if you want to copy it.
Now thats a neat idea
Rus
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To take the IBM mainframe example he quotes: yes, IBM originally used a CKD (count-key-data) architecture and this was still preferred in the late 1970s for highest performance applications. However, in the last 1970s, IBM already provided FBA (fixed block architecture) disk drives such as the 3370. These moved intelligence of disk geometry into the disk controller and were quite easy to program.
Other mainframe and minicomputer manufacturers had innovative schemes during the early 1980s.
I don't know about you, but 99.9% of the the time the people that ask me about a computer:
a) have no clue about the difference between hard drive space and RAM memory.
b) "just want to get online", but have no clue what that really means.
I've set a few people up with old PII/350's, just to get them a computer in the first place... it gets them online and they can browse the web, email, etc. I tell them, rather than spend $1000 today to buy a machine, spend it next year and use the 350 to get a clue about what it is you want.
It works. Generally they buy some game that won't run well on less than an 833 or something, and while they still don't know what the difference between a "megahertz" and a "gigahertz" (and no, trying to explain the metric system to them doesn't work), they at least have a better idea of what a computer *is* and what they want to do with it.
*Then* I make a recommendation on what they need based on what they want to do with it.
second that. not only do they blame you for everything, they'll treat you as a repairman, calling you up anytime they have a "problem" and expecting you to give them the same service as a paid technician. its nice when people appreciate my efforts, but for the most part its quite pointless. i now restrict my services to close friends only who have manners and don't behave like i owe it to them.
You probably mean you used one of those compression programs like Stacker or Double/DriveSpace.
The problem is that they don't know how much disk space you have, since it depends on the compressability of the data. Sometimes you would need to write something large to the drive, and the installer would tell you that there's not enough space, although it would have fit. That happens because some data compresses really well. A MP3 won't compress at all, but something like a 16 color image might compress really well.
So, for these cases you can adjust the estimated compression ratio. You tell the program you expect files will compress to 1/8 of their size, and it adjusts the free space estimation. That's all. Data won't compress any better because of it. I saw lots of people setting a huge compression ratio thinking that seeing 10 times more "free space" would somehow let them put 10 times more stuff on it.
For a demonstration, I made a "32 MB" 1.44MB floppy, and showed how it got full with 2 MB of files.