Dos Command

Essential DOS Commands and Concepts

Introduction

DOS (an acronym for Disk Operation System) is a tool which allows you to control the operation of the IBM PC. DOS is software which was written to controlhardware. IDRISI, Atlas*GIS, Microstation, AutoCAD, CPS/PC, and ARC/INFO are, in turn, application software which run under DOS. By this we mean that, although IDRISI, Atlas*GIS, Microstation, AutoCAD, CPS/PC, and ARC/INFO were written to accomplish a single task or application (in this case manipulation of spatially related data), they must use DOS to pursue its work.DOS can be used for a wide range of tasks far beyond the requirements of this class. You will be able to manage well if you master only a small subset of DOS commands and functions. These relate almost exclusively to file and directory management and are introduced in this handout.
This tip sheet assumes that you have learned how to turn on the PCs as they are configured in room 230 and that you have familiarized yourself with their keyboards (no small task in itself). It also assumes that you understand the meaning of the concept of a file and the elements of a file specification (drive, filename, and extension). The microcomputers you will be using are equipped with two floppy disk drives. The A-drive is the 3.5" (1.44MB) drive and the B-drive is the 5.25" (360KB) drive. The microcomputers also contain a C-drive, a hard disk drive of 130MB or 200MB capacity.
You will quickly find that the best way to learn how to use a computer is through experimentation. That is, once you have learned a command, try some variations until they don't work, then start over. Often there are five or six ways for you to accomplish a particular task. Usually, I will introduce you to only one, leaving it up to you to discover the rest. Don't hesitate to consult the DOS Reference Manual; copies can be found on the bookcase in room 230. Finally, don't be unduly disturbed by error messages. With computers, one of the best ways to learn is by making mistakes.
Most of the common DOS commands you need to use for this class (copy, rename, delete) are available to you in Windows through the Filemanager icon. And, since you can move back and forth between DOS and Windows, it doesn't matter which option you employ. Some commands are faster in invoke in Windows, some in DOS. If you haven't worked with Windows previously, go to the Windows tutorials in the help area.

Backup Files

It is possible to lose files by mistake, although the more you practice the less likely it becomes. For your own peace of mind, it is good practice to make backup copies of your most valuable files on a separate diskette. Store your backup disk in a safe place and don't carry it through a metal detector. Use the COPY command to create the backup.There is no need to backup every file you create, only the ones in which you've invested much work. Also, prune your backup diskette every week or two using the ERASE command. Backup files which have been made redundant by subsequent additions will simply create clutter on your backup diskette. An effective file naming convention is essential to keeping track of your backups.

Change the Default Drive

To change the default drive, simply type the letter of the your choice. The new default will be listed in subsequent DOS prompts.Example:

C> A: [enter]
Changes the default drive from C to A.
A> C: [enter]
Changes the default drive from A to C.

[enter] means that you must press the Enter Key before the format command will execute. [Enter] is required after any DOS command, it is assumed in all commands found below.

CHDIR (CD) Change Directory Command

Once you have located the directory you want, you may move from directory to directory using the CD command (change directory)Example:

C> cd furniture
Moves you to the directory called 'FURNITURE'
C> cd \furniture\chairs
Moves you to the directory called 'CHAIRS' under the directory called 'FURNITURE'.
C> cd ..
Moves you up one level in the path.
C> cd \
Takes you back to the root directory (c: in this case).

COPY Command

The COPY command can be used both to copy files from disk to disk or to create a second copy of a file on a single disk. (There are many more uses of the COPY command, but only the basic operation is discussed here.)Example:

C> copy c:kermit.exe a:
Copies the file 'KERMIT.EXE' from the C drive to the A drive and gives it the same name.
C> copy a:brazil1.dat b:\south\brazil2.dat
Creates a copy of 'BRAZIL1.DAT' from drive A on drive B, putting it in the 'SOUTH' subdirectory and renaming it 'BRAZIL2.DAT'.

The key to use this command correctly is to remember that the first file specified after the COPY command is the source file, the second is the target:ehp1 file. Thesource is the file to be copied. The target will be the location and name of the new file. If the file name and extension are omitted after the target's drive specification, the new file will have exactly the same name as the source file.Example:

C> copy a:myfile.txt b:
C> copy c:command.com b:com.com
C> copy b:golly.gee a:whao.boy
C> copy command.* a:
C> copy a:mymap.dwg c:\maps

Note: it is always good practice to us the complete file specifications for both source and target files, Be very sure of yourself before you accept defaults or employ wild-card characters. Otherwise you may end up with some interesting results. Incomplete or incorrect source names may result in errors, such as the command: copy edlin a:myomy.bat. Try it and see what happens.

DIR (Directory) Command

The DIRECTORY command lists the names and sizes of all files located on a particular disk.Example:

C> dir a:
Shows directory of drive A
C> dir b:
Shows directory of drive B
C> dir \agis
Shows files in a subdirectory on drive C (default)
C> dir
Shows directory of drive C
C> dir /w
Shows directory in wide format, as opposed to a vertical listing.

All the files are listed at the screen, you can stop the display by typing CTRL-BREAK. If you ask for a directory on the A or B drives, be sure there is a diskette in the drive and that the diskette has been formatted. If the drive is empty, or if the diskette is unformatted, the DOS will respond with an error message.

DIR Options

Two little characters, '*' and '?', will make your life with computers much easier. Their use is illustrated below.Example:

C> dir a:*.ex
Lists all files on the A drive with an extension of 'EXE'.
C> dir b:kermit.*
Lists all files on the B drive with a filename of 'KERMIT'.

The asterisk is a wild-card character which allows the user to enter only a limited part of a file specification to find a file. It is useful when you wish to locate a group of files with the same filename or the same extension. On other occasions you may have forgotten part of a file specification. You can use '*' in place of the parts of the specification you have forgotten. Similarly, '?' permits wild-card searches keyed to single characters.Example:

C> dir a:labe?.com
Lists all five-letter files with the first four letters 'LABE' and an extension of 'COM'.
C> dir b:format.c??
Lists all files with a filename of 'FORMAT' and an extension beginning with 'C'.

Wild-card characters can be used in combination.Example:

C> dir a:labe?.*
Lists all five-letter files with the first four letters 'LABE' and any extension.
C> dir c:*.ex?
Lists all files with an extension beginning with 'EX'.

Experiment with '*' and '?' to improve your ability to find files quickly. These wild-card characters can also be used with several other DOS commands.

ERASE Command

The ERASE command deletes specified files.Example:

C> erase a:myfile.txt
Erases the file MYFILE.TXT from the diskette in the A drive. If no drive specification is entered, the system looks to delete the specified file form drive C (in this case).

IMPORTANT WARNING: This command is easy to use, but it is the most dangerous one you will encounter in DOS (apart form FORMAT). If you aren't careful, you may delete a file which you--or someone else--needs. And, unless you have saved a backup of that file, the erased file is gone for good. For this reason it is good practice to use only complete file specifications with the ERASE command (and to keep backups of your most valuable files). As a safety precaution, never use the wild-card characters '*' and '?' in ERASE commands.BEWARE: I will rescind your laboratory privileges for a full week if you ever knowingly use either the command: erase c:*.*, or the command: erase *.*. Guess what happens?

File-Naming Conventions

Careful file naming can save time. Always choose names which provide a clue to the file's contents. If you are working with a series of related files, use a number somewhere in the name to indicate which version you have created. This applies only to the filename parameter; most of the file extension parameters you will be using are predetermined (or reserved by DOS for certain types of file).Example:

WORLD.DAT
An ATLAS*GRAPHICS file containing data for a world map. The DAT extension is required by ATLAS*GRAPHICS.
BRAZIL.BNB
A boundary file of Brazil in binary form.
BRIT1.DAT
BRIT2.DAT
BRIT3.DAT
Three versions of a data file for a map of Britain.

FORMAT Command

You must format new disks before using them on the IBM computers. The format command checks a diskette for flaws and creates a directory where all the names of the diskette's files will be stored.Example:

C> format a:
Formats the diskette in the A drive.
C> format b:

After entering this command, follow the instructions on the screen. When the FORMAT operation is complete, the system will ask if you wish to FORMAT more diskettes. If you are working with only one diskette, answer N (No) and carry on with you work. If you wish to FORMAT several diskettes, answer Y (Yes) until you have finished formatting all your diskettes.BEWARE: Executing the format command with a diskette which already contains files will result in the deletion of all the contents of the entire disk. It is best to execute the format command only on new diskettes. If you format an old diskette make sure it contains nothing you wish to save.

MKDIR (MD) Make Directory Command

This command creates a new directory.Example:

C> mkdir mine
Creates a directory called 'MINE'

Rebooting the computer (Ctrl-Alt-Del)

In some cases, when all attempts to recover from a barrage of error messages fails, as a last resort you can reboot the computer. To do this, you press, all at once, the control, alternate and delete.BEWARE: If you re-boot, you may loose some of your work--any data active in RAM which has not yet been saved to disk.

RENAME (REN) Command

The RENAME command permits users to change the name of a file without making a copy of it.Example:

C> ren a:goofy.txt pluto.txt
Changes the name of 'GOOFY.TXT' on the A drive to 'PLUTO.TXT'.

This command is very simple to use, just remember two points: the file name and extension must be complete for the source file and no drive specification is given for the target. Renaming can only occur on a single disk drive (otherwise COPY must be used).

RMDIR (RD) Remove Directory Command

This command removes a directory. It is only possible to execute this command if the directory you wish to remove is empty.Example:

C> rd mine
Removes directory called 'MINE'.

Stop Execution (Ctrl-Break)

If you wish to stop the computer in the midst of executing the current command, you may use the key sequence Ctrl-Break. Ctrl-Break does not always work with non-DOS commands. Some software packages block its action in certain situations, but it is worth trying before you re-boot.

Converted 20 July 1994. KEF.

Alienware M11x: World’s Smallest Gaming Laptop

The Alienware M11x first hit headlines in January at the 2010 Consumer Electronics Show. Even without testing the unit, we could see that there was some real potential in the component selections. ASUS already showed us with their UL series that overclocked CULV processors can easily cope with most modern games, provided they have a GPU that is up to the task. The UL series uses GeForce G210M graphics cards, and while they’re substantially faster than any current IGP solution, they still struggle with running many games at anything more than low/minimum detail settings. A faster GPU is necessary for higher quality settings, but where exactly does the bottleneck shift from the GPU back to the CPU when we’re dealing with overclocked CULV? The M11x looks to answer that question by going with a rather potent GeForce GT335M.

Alienware M11x Specifications
Processor	Core 2 Duo SU7300 (45nm, 2x1.30GHz, 3MB, 800FSB, 10W) Pentium SU4100 (45nm, 2x1.30GHz, 2MB, 800FSB, 10W)Overclockable to 1.73GHz
Chipset	Intel GS45 + ICH9M
Memory	2x1GB to 2x4GB DDR3-10662x2GB DDR3-1066 Tested
Graphics	NVIDIA GeForce GT 335M Intel GMA 4500MHDSwitchable Graphics
Display	11.6" LED Backlit WXGA (1366x768)
Hard Drive(s)	160GB 5400RPM 250GB 7200RPM 320GB 7200RPM500GB 7200RPM 256GB SSD
Optical Drive	N/A
Networking	Gigabit Ethernet (Atheros AR8132 / L1c) Dell DW1520 802.11n WiFi Bluetooth (Optional) Mobile Broadband (Optional)
Audio	HD Audio (2 speakers with mic and 2x headphone jacks)
Battery	8-cell 63Wh
Front Side	N/A
Left Side	Mini 1394a FireWire Flash Memory Card Reader DisplayPort HDMI Gigabit Ethernet 1 x USB 2.0 (powered) VGA Kensington Lock
Right Side	2x Headphone jack Microphone jack 2 x USB 2.0
Back Side	AC Power Connection Cooling exhaust
Operating System	Windows 7 Home Premium 64-bit Windows 7 Professional 64-bit Windows 7 Ultimate 64-bit
Dimensions	11.25" x 9.19" x 1.29" (WxDxH)
Weight	4.39 lbs (with 8-cell battery)
Extras	AlienFX Zoned Lighting Webcam 86-Key LED Backlit Keyboard 3-in-1 Flash reader
Warranty	1-year standard warranty Remote diagnostics 3-year and 4-year extended warranties available Advanced and Premium In-Home Service available
Pricing	Starting at $799 Test System: $1099 ($1198 with TactX Mouse)

Like the G210M, the GT335M supports DirectX 10.1 functionality and is built on a 40nm process technology. That’s where the similarities end. The GT335M bumps the SP count from the 16 in the G210M all the way up to 72 SPs, providing much more computational power; similarly, the memory interface is 128-bit instead of 64-bit. The actual core and shader clocks on the G210M are slightly higher: 625 core and 1500 shader versus 450 core and 1066 shader on the GT335M; memory speed on the other hand is bumped from 1600MHz to 2133MHz. The result is that the GT335M has 166% more memory bandwidth and 224% more computational power… all with the same overclocked CULV SU7300 (or SU4100) processor as the ASUS UL series.

Of course, the GT335M isn’t the only game in town when it comes to faster mobile GPUs. We recently reviewed the ASUS N61Jv with an i5-430M CPU and GT325M GPU, so that will be an interesting matchup from the performance standpoint. GT325M cuts the SP count down to 48, with a slightly lower shader clock as well, but it has the same memory bandwidth. With 63% more computational performance, the GT335M should be noticeably faster than the GT325M, but GPU memory bandwidth is often the bigger bottleneck on 128-bit GPUs and the N61Jv CPU is substantially faster than an overclocked SU7300 CULV. In games that are CPU limited on the M11x, we’ll see the N61Jv come out ahead (or at least close the gap), whereas GPU limited games should still prefer the M11x. Of course, there’s no getting around the size advantage of the M11x: it weighs less and has a chassis that’s much more portable. Really, there’s no competition for the M11x unless you’re willing to move to a 13.3” chassis. In that case ASUS has the UL30Jc, but that has a G310M GPU (a 2% higher shader clock than the G210M) so it’s still a big step back in terms of gaming potential.

The base model M11x comes with 2GB DDR3, a 160GB 5400RPM hard drive, and a Pentium SU4100 processor. Our test unit bumps the CPU up to the Core 2 Duo SU7300 for $100 extra; considering the only difference is 3MB L2 cache (versus 2MB on the SU4100) and support for VT-x (hardware virtualization), most users will be better off saving the $100 for other upgrades. The 500GB 7200RPM Seagate 7200.4 hard drive, on the other hand, is a very welcome addition. It should offer improved performance relative to 5400RPM drives while still providing a lot of storage capacity. The $150 to upgrade the hard drive is a bit steep, though, considering you can purchase the same drive for $85. Finally, Alienware shipped us a system with 4GB DDR3 (another $50), which brings the total price of our system to $1200. Obviously this isn't a cheap laptop, but if you take the base system and just add 4GB RAM (and clone the HDD to your own HDD/SSD when you get it) you can get everything you need for under $1000.

The short summary of the M11x is simple: it’s the smallest laptop ever made that can still manage to play games. Really. There’s nothing else even close when you get down to sub-14” laptops, and it can outgame many 15.6" and larger notebooks. Not only can it run every current game on the market, but we managed to get 30+ FPS at medium or higher detail settings in every game we tested! That’s the good news. The bad news is that a great design is once again saddled with a mediocre LCD, and Alienware omitted at least one feature that they really need: NVIDIA’s Optimus Technology. We don’t mind manually switching between IGP and discrete GPUs that much (though it was odd to see Dell’s Data Safe Online Backup utility trigger a block a few times—the toaster.exe process); far more important is that Optimus laptops will get better driver support in the future. We already encountered several games that complained about our drivers (for example, Batman and Left 4 Dead 2) and we suspect things will only get worse. NVIDIA has yet to deliver a Verde driver with Optimus support, but that should come in the next release. If you want new drivers for switchable graphics laptops like the ASUS ULx0Vt series and the M11x… well, don’t hold your breath.

Finally, we should mention that while the M11x technically has an 11.6” chassis, a few aspects of the chassis need mention. First, the M11x is about 1” deeper than other 11.6” CULV laptops we’ve looked at, and at 4.4 lbs. it definitely weighs more. Obviously, Alienware had to pack more cooling capacity into the M11x to keep the GPU and CPU from overheating, but they’re dangerously close to the size of a 13.3” chassis. Look at the LCD bezel and you’ll find a large border, particularly on the top and bottom. The M11x uses an 11.6” 1366x768 LCD, but with a few small tweaks we’re confident they could have put a 13.3” 1440x900 WXGA+ LCD into the chassis. The huge bezel area almost makes us think that they put a smaller LCD in the chassis just so they could lay claim to having an 11.6” gaming laptop. Personally, I would have preferred a 16:10 aspect ratio with a 13.3” LCD—besides, even if this were a 13.3” laptop, it would still be over twice as fast as the nearest competitor in graphics power!

Minor blemishes aside, there’s still no getting around the fact that this is a very capable gaming laptop with a very small footprint. The total performance on tap should be about equal to that of the Gateway P-6831 FX that we praised a couple years ago. The overclocked CULV processor is faster and uses far less power, and the same goes for the GT325M (though the old 8800M did have a memory bus that was twice as wide). Add in switchable graphics and you have a laptop that weighs roughly half as much and lasts two to four times as long on battery power. Join us as we take a closer look at what makes the M11x tick and run it through our benchmark suite.

AMD'S Turbo Core

AMD Divulges Phenom II X6 Secrets, Turbo Core Enabled

Last month Intel introduced its first desktop 6-core CPU, the 32nm Gulftown Core i7 980X. Running at 3.33GHz we loved the fact that it’s quite possibly the first Extreme Edition part that is able to justify its price. For $999 you get six cores and better performance all in the same power envelope as the current high end quad-core i7s.

The 980X is a great chip, but spending $999 on a single component in your PC is a tough sell for most folks. Luckily, AMD is coming out with its own 6-core processors codenamed Thuban. Below is what we know so far about AMD's Thuban lineup (note, the information in the table was not provided by AMD):

AMD 2010 Roadmap
CPU	Clock Speed	Max Turbo (<= 3 cores)	L3 Cache	TDP	Release
AMD Phenom II X6 1090T	3.2GHz	3.6GHz	6MB	125W	Q2
AMD Phenom II X6 1075T	3.0GHz	3.5GHz	6MB	125W	Q3
AMD Phenom II X6 1055T	2.8GHz	3.3GHz	6MB	125W/95W	Q2
AMD Phenom II X6 1035T	2.6GHz	3.1GHz	6MB	95W	Q2
AMD Phenom II X4 960T	3.0GHz	3.4GHz	6MB	95W	Q2

Officially branded the Phenom II X6, AMD won’t be launching these processors until some time in the future. But today AMD is disclosing some basic details about the parts. We’re also mixing in our knowledge of internal AMD roadmaps to paint a clear picture of AMD’s 6-core strategy.

The more cores at the same TDP feature that Intel delivers with the 980X, AMD is also promising with Phenom II X6. The difference is that these are still 45nm parts. While we’ll have to test them to be sure, AMD currently indicates that the entire Phenom II X6 lineup will be rated at 95W or 125W TDPs. It’s all manufacturing tricks that make it possible (good job GlobalFoundries). In theory you should be able to buy a Phenom II X6 and have it operate in the same power envelope as a Phenom II X4 965.

With the Thuban cores AMD is introducing its version of Intel’s Turbo Boost technology called Turbo Core. AMD has yet to implement power gating on its processors, so Turbo Core works a little differently than Intel’s Turbo.

Turbo Core kicks in when 3 or more cores (on a 6-core part) are idle. When this happens, the frequency of those three cores is reduced to 800MHz, the voltage to the entire chip is increased, and the remaining three cores are turboed up by as much as 500MHz. It doesn’t get any more granular than this. If you have 3 or more cores idle, then the remaining turbo up. In any other situation the CPU runs at its normal clocks.

The CPU handles all monitoring and does the clock/voltage management itself. The switch to turbo up cores apparently happens fast enough to deal with Windows moving threads around from core to core.

Turbo core is triggered by a deterministic system that is based on load demand and current operating conditions (not temperature).

Cool’n’Quiet is active throughout the turbo process. What actually happens is that when CnQ looks to see if a set of cores should be downclocked, it also has the ability to increase the frequency of other cores.

This isn’t nearly as elegant of a solution as Intel’s turbo. The idle cores are never actually shut off, and voltage to all cores is increased to reach the higher clock speed. However if it works as advertised with no drawbacks (e.g. underclocking 3 cores when you actually still need them) then it’s definitely better than nothing for the Phenom II lineup. AMD will also have quad-core CPUs with turbo core support based on the new Thuban cores.

The great news? All Socket-AM3 and AM2+ motherboards will work with these new Phenom II X6 CPUs with nothing more than a BIOS update. The boards do have to support the TDPs the chips are rated for of course.

Pricing and performance are both unknowns at this point. We’ll keep you posted!