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Improved separation of FDC media parameters from drive parameters

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Jeff Parsons 2014-10-20 00:24:13 -05:00 • committed by jeffpar
commit 1809543577
32 changed files with 1915 additions and 1887 deletions
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blog/2014/10/17/README.md
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@ -16,7 +16,7 @@ when the keyboard's "clock" line is toggled (see *set8042CmdData()* in [chipset.
a 40-track diskette).
+ The BIOS Diskette Reset function does something odd after resetting the Floppy Disk Controller: it
issues not one but *four* "SENSE INTERRUPT STATUS" commands to the FDC, and expects each response to
return an incrementally larger drive number. I found this a bit mystifying, considering that the IBM's
return an incrementally larger drive number. I found this a bit mystifying, considering that IBM's
own FDC/HDC "combo card" supports a maximum of *two* diskette drives. But, there's no point in arguing
with a BIOS that's almost 30 years old.
+ The BIOS attempts to detect what its authors must have considered a common problem: failure to run SETUP
@ -28,22 +28,22 @@ to discover that the ATC had this behavior, and now I'm wondering how many other
immediate "STATUS" register updates.
This PCjs release also fixes a problem reported by a user: if you disable **localStorage** support in your
browser, previous versions would fault. I knew that every browser that supports PCjs also supports
**localStorage**, but I didn't consider what might happen if a user had decided to turn it off.
browser, previous versions of PCjs would fault. While every browser that supports PCjs also supports
**localStorage**, I didn't consider what might happen if a user decided to turn it off.
The only downside to turning off **localStorage** is that none of your PCjs machines will be able save/restore
their state when you leave/return to the page, so they will always reboot.
their state when you leave/return to the page; they will always reboot.
Browser's don't always refer to the **localStorage** feature by its actual name, either. For example, in
Chrome, the setting that enables/disables **localStorage** is hidden under "Advanced Settings" => "Privacy" =>
"Content Settings" => "Cookies" => "Allow local data to be set (recommended)". Which is a little misleading
and annoying, because **localStorage** != **cookie**.
"Content Settings" => "Cookies" => "Allow local data to be set (recommended)". Which is somewhat misleading
and a little annoying, because **localStorage** is *not* a **cookie**.
PCjs *never* sets any cookies. Cookies are bits of data that your browser saves and then automatically sends
off to the server every time you make a request. **localStorage** is nothing more than local storage. Granted,
a JavaScript application could certainly abuse it and send it around like a cookie, but PCjs doesn't do that.
The only exception is when PCjs detects a problem, and even then, you must first agree to submit your machine's
state as part of the bug report.
off to the server every time you make a request. **localStorage** is nothing more than local storage; it is
*not* automatically sent anywhere. Granted, a JavaScript application could abuse it and send it around like a
cookie, but PCjs does *not* do that; the only exception is when PCjs detects a problem, and even then, you must
first agree to submit your machine's state as part of the bug report.
*[@jeffpar](http://twitter.com/jeffpar)*
*October 17, 2014*