Dr. Jerry Pournelle

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Mailbag for July 31, 2006
Jerry Pournelle jerryp@jerrypournelle.com
Copyright 2006 Jerry E. Pournelle, Ph.D.

July 31, 2006

We had many letters about last week's story of disconnecting mapped network drives, and drive management. I have chosen some of the most useful:

Subject: Disconnecting drives and such silliness

Dear Dr. Pournelle,

Microsoft's UI is usually workable and sometimes almost pleasant. However, as you noted, it is painfully slow for certain operations. In my opinion, it is high time they decoupled UI delays fromnetwork/hardware related timeouts. I'm the user, don't make me wait!!!

It is possible to speedily break an unavailable network connection without making the interface go bonkers. Get a command line window up (cmd.exe) and use this command:

net use /delete x:

Where x: is the drive letter of the offending connection. Despite many UI advances, sometimes it's better to avoid it.

Thank you for many years of thoughtful and enjoyable prose.

Timothy Meekhof

Dr. Samuel Johnson once said that men seldom need educating, but they often need reminding. This is certainly one of those cases: I have known this for years, but somehow I managed to forget it. The command line operation works very well. One caution: it takes a few seconds for "My Computer" to notice that one of its connections has been deleted, so the deleted drive letter may show up if you open My Computer soon after you do the command line deletion.

The next letter explains in more detail how to manage drive letter assignments.

Unmapping Network Drives


It's been so long since I've used My Computer/Windows Explorer to map/unmap a network drive letter, I've practically forgotten how. To avoid the kinds of network delays you've encountered, I've always found it more expedient to go to a "DOS" prompt and type commands like "net use j: /d" to unmap, say, the J: drive.

Also: recently I encountered problems with my computer refusing to give up drive letters when I unplugged USB devices, requiring reboots to rectify. I discovered a really nifty workaround (at least for Windows XP):

I have my flash drive mapped to "C:\Flash". I can browse its contents just as if it were on my local hard drive. Deleted files even go into the Recycle Bin.

This works so splendidly that I'm still doing it this way, even though I eventually resolved the drive-letter problem. (A conflict with "Spyware Doctor", which went away when I uninstalled the software.)

One obvious benefit: freeing up drive letters.

Note that you can temporarily map both a drive letter *and* an NTFS folder if, say, your disk defragmentation software requires a drive letter to operate.

Another useful "DOS" command is "subst". I have a wonderful file synchronization utility called "Beyond Compare", by Scooter Software, which expects to see the backup device on the "I" drive. Since I have multiple devices, I can change them on the fly as follows:

   subst i: c:\flash       -- Now backing up to the Flash drive
   subst i: /d             -- Now freeing up the I: drive
   subst i: g:             -- Now backing up to my Zip 750 drive on G:

Hope some of this is useful to you,

Bob Shepard

Note that the syntax "net use j: /d" works as does "net use /delete j:". I found that surprising when I tried it. I continue to do silly things so you don't have to.

I must admit I had entirely forgotten about the subst commands, and I am finding that very useful. For those interested, get a command line and do "subst /?" to see what all can be accomplished.

I used to do a great deal of work through command lines. As the Windows GUI got better, I fell out of the habit; but given that many things done by command line are instantaneous while the Windows GUI takes an age to do them, it's clear that it's worth staying in practice.

In another letter, Dennis Healy reminds us that you can get to Disk Management from a command line window by typing "diskmgmt.msc"; and that most of this can be accomplished in GUI from there by right clicking various drive letters.

Disk Management doesn't look for the state of mapped net connections so disconnected/slow net shares don't affect it.

First law on holes -- when you're in one, stop digging!

Denis Healey

I do wonder if all the command line structure will be kept in VISTA?

And a reminder that batch files still work, and "net use" and "subst" commands can be included in them:

Network Slowdowns

Dr. Pournelle, you wrote in Chaos Manor Reviews for July 24:

"Satine is noticeably slow at some tasks. In particular: I have a number of drives mapped to other machines. Those machines have been turned off because of the heat. Disconnecting Satine's mapped connections to those drives is painful."

I have various computers on my home network which are up and down on an irregular basis, depending on need. I use the NET USE command in a batch file to turn remote drives on and off. Perhaps this may help?

The new column looks good. I has set myself a reminder to re- subscribe when my current subscription runs out in November.


Harry Payne

Thank you for that reminder. And finally a recommendation of a program I have not yet had a chance to try; indeed, what with "net use" and "subst" and batch files coupled with the GUI "Disk Management," I am not sure more is needed, but for those who want automated shell management, read on.

USB Drive Letter Manager

Hi Jerry

You wrote in CM Reviews about USB and Drive letters I saw this at Shell Extension City and thought it may help you.


Take Care

Kirk Patchett

Changing the subject:

Subject: Monk's cell meets Pournelle settings

Dear Jerry-

I have been a long time reader of your Chaos Manor column and was pleased to recently discover your new home at chaosmanorreviews.com. You were the only reason I subscribed to the Byte website and that subscription will now be directed to this new site.

I have always related to your description of the "Monk's Cell" and removing all distractions when you needed to write. I relate to that as I do the same thing when I need to deep think about a project at work at something greater than my usual level of continuous partial attention. While browsing through my blog subscriptions I came across a product that looked almost as if you had specified it. Nothing on the screen except for text and built in blue-on-white color scheme. If nothing else I thought you would enjoy seeing it.


I am not affiliated with these cats in anyway, just liked the look of the product.

Kind Regards--

Richard Guy

Niven and I got accustomed to white letters on a blue screen with no distracting tool bars when we changed from our CP/M WRITE program (written by Tony Pietsch) to Symantec Q&A for DOS. Q&A was a marvelous program for its time, combining a data base, word processor, intelligent assistant, and considerable power for decision making programming. I have never understood why Symantec did not continue to develop it. In any event, Q&A Write has white letters on a blue screen, and Niven and I got sufficiently accustomed to it that I told Chris Peters that was the main reason we didn't try Microsoft Word. Chris promptly met that challenge and we've been using various flavors of Word ever since. Niven still likes white letters on blue, but over the years I have got used to plain old black on white. Black on white has far more light coming out of the screen, and thus a higher dazzle factor, so in theory I ought to prefer white on blue, but so much other work requires me to read black letters on a white screen that I fell out of the habit of making the change when working on my own stuff.

Today I am looking at my screen with a bright window behind it and I'm thinking of going to white on blue...

Subject: Chaos Manor Reviews - Column 309, March, 2006

Re: BootCamp and disk sharing you say:

A better way is to network both computers through Samba (SMB), a file sharing protocol. This is what we use here to send files to and from my (older, PowerPC) PowerBook. Use a second physical machine as a server (it can be another Mac, or a Windows system, configured either as a server or as a workstation), save to that, and once again, when one part of your Intel Mac is asleep the other will be awake and able to read and write files through the network.

"A second physical machine as server" - have you contemplated much on NAS? I have just bought a wonderful - not NAS exactly - a quad IDE USB RAID box in which to stick four Barracudas - but NAS is on the march, in the form of such devices as the Buffalo TeraStation, as well as other smaller devices (not to mention the big enterprise frames). Even my quad USB box replaces a server with a 450W PS and about ten times the cubic volume - and the drives run cooler, it seems. "And there was much rejoicing."

The 'second physical machine' is like recycling a big CRT - good results, zero capital cost, but aesthetically and in second-order effects (heat, power, desk space) it often pays to spring for a new LCD - or, in this case, perhaps a NAS device. It sits next to my machine rack and I feel much better about it now. Quite worth the $159 plus $30 shipping, so it seems. Perhaps I would like the performance of 1000BaseT better than USB 2.0, but USB seems to clobber my old 100BaseT performance levels - no video skipping, though whether due to bandwidth or resolution of drive heat issues, who knows?.

One thing, file systems are still a battle with these new NAS it seems. Many do not run NTFS - relying on Linux, they use somethng called EXT3 (no se) or allow FAT32 with limits as you describe. Perhaps as SMB the File system matters not to the user, I could not say in detail. It might be worth spending $100 or so to tinker. I am happy as a clam to have shed that old Frankenstein, though.

(BTW, I went to those sites you recommended for detailed perf reviews on jerrypournelle.com; one reviews a NAS device but I found the review detail superficial - didn't treat the filesystem at all. No doubt you could do better ;>)

Best, Noah

PS Mine is the CyberBox CF-B4044U, per the Chinese (? Sondyo Computer Co. c.2005) translated manual. From http://cooldrives.stores.yahoo.net/ which sold me this and has many fancier ones, USB, FireWire, NAS; IDE, SATA; single, double, quad; hot-swappable; etc., etc.
  Thx N

Name                     Code                Qty    Each  Options
Quad Drive USB 2.0 RAID  CGS-2TB-RAIDU         1  159.98
Disk Array System up to
                                        Subtotal  159.98
                                        Shipping   29.79
                                           Total  189.77

Thanks for the confidence. I might be better able to do that work, but I am flat out of time.

I suspect I should rethink my decisions on using older machines for networked storage, but I do find that 1000BaseT to NTFS files on a "box of drives" is a very good backup system indeed. Do note, though, that when I built my office suite here, we included a small sound insulated room intended for printers; that was when my manuscripts were printed on a Diablo, an impact printer, and printing a large document was noisy enough to be traumatic. After the office was finished but before I moved into it, I got one of the first HP LaserJet printers, and it worked so silently and so well that it is in the office with me. That left the "printer room" to become the "cable room" where all network cables go, and I can keep several older machines and servers in there. An economical room air conditioner serves that room, and the room is small enough that the cost for doing that is low.

I do have a Mirra Linux-based backup system in there as well; but my primary backup remains multiple copying to "box of drives" machines built out of retired systems. Of course I build a lot of "latest and greatest" machines and change main machines more often than anyone not writing about them would.

Subject: Net neutrality

Dr. Pournelle

On the "net neutrality" issue:

Note the two links (the pieces by Peter Klein and Tim Swanson) towards the end.

-- KE

The net neutrality issue divides many people who otherwise agree. The question is whether we trust the market or the government. My inclination is always toward the market, but one needs to keep in mind Adam Smith's dictum that two capitalists seldom meet without conspiring to find ways to get the government to restrict entry into the market...

And finally a correction:

Subject: Your Kodak camera reveiw

In your column of July 24, you mention your Kodak V750 camera, but I can only find a Kodak V570 listed on the Kodak site. I noticed that some other reviews for the V570 occasionally inadvertantly refer to it as the V750. Can you shed some light on this? Is it called the V570 when one lens is used, and V750 when using the other?

Thanks for your pragmatic and comprehensive reviews and commentary.

-Jim Melendy

It's the V570 throughout. The number isn't written very clearly and I probably got distracted when transcribing it. Thanks for noticing, and for the kind words.

To Be Continued...