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COMPUTER BITS BY JASON COLE Win95, MSDOS.SYS & the Registry Do you want to stop the Windows 95 boot logo from ap­pearing each time you start Windows 95? Or do you just want to stop the computer from re-booting into safe mode if you haven’t previously shut down Windows 95 correctly? You can do all this and much more by editing the msdos.sys file. Fig.1: Typical MSDOS.SYS File [Paths] WinDir=C:\WINDOWS WinBootDir=C:\WINDOWS HostWinBootDrv=C [Options] BootDelay=1 BootMulti=1 BootGUI=1 Network=1 BootWarn=0 Logo=1 ; ;The following lines are required for compatibility with other programs. ;Do not remove them (MSDOS.SYS needs to be >1024 bytes). ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxa ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxb ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxc ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxd ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxe ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxf ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxg ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxh ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxi ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxj ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxk ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxl ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxm ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxn ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxo ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxp ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxq ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxr ;xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxs 70  Silicon Chip Turning off your computer without first correctly shutting down Windows 95 is generally not a good idea. Doing so can cause unallocated file errors on the HDD (hard disk drive) and this can cause all sorts of problems. These file errors are caused by programs that have not been allowed to terminate normally. As a result, socalled temporary files (ie, .tmp files) are left in the temp directory on your hard disc. In greater detail, temporary files are files that are created as a program works. If the program is not terminated correctly, these temporary files remain on the hard disc when you shut the computer down, which means that the FAT (file allocation table) is not correctly updated. But inevitably, there may be times when turning off the computer while Windows is still open is required (or it can just happen if there is a power failure) If so, you don’t really want it rebooting into safe mode or asking you any ques­tions. You may also not want the Windows 95 splash screen (or boot logo) to appear because you want to check for errors in config. sys and auto­exec.bat when booting Windows 95. Alternatively, you might want the boot menu options to always appear, or you might need to prolong the boot delay. Programmers and hardware designers occasionally require these options so that they can test new ideas. The answer is to edit the msdos. sys file. Editing msdos.sys Msdos.sys for Windows 95 has changed since the version that came with MSDOS 6.22 in that it is now quite readable when opened in a text editor. This means that you can easily modify it your­self to give the startup options that you require. The msdos.sys file lives in the root directory of the HDD and has hidden, read-only, system attributes. If you want to play around with this file then go for it but first, make a backup of the file and make sure that you have a working boot disk, just in case things go wrong. That way you can easily copy the original back later if something goes wrong. Once you’ve made the backup, undo the attributes (type attrib -r -h -s msdos.sys at the command prompt) and open the file with a text editor. The resulting file will look similar to that shown in Fig.1. From the [Options] section in Fig.1, you can see that this machine operates as follows: (1) it has a boot delay of one second (Bootdelay=1); (2) it can boot into the previous version of DOS, giving it dual boot capabilities (BootMulti=1); (3) it boots the machine straight into Windows (BootGUI=1); (4) the network will be active (Network=1); (5) there will be no warning if Windows has previously been shut down by just turning off the computer (BootWarn=0); and (6) the splash screen will be displayed (Logo=1). However, these are just some of the possible options and you can easily add in other options yourself and alter the exist­ing options to suit. Note that if the option isn’t listed in the msdos. sys file, the system takes the default action. Fig.2 shows a list of some other (but not all) options for the msdos.sys file. Note that most settings require a value of 1 (ON) or 0 (OFF). The other entries in Fig.1 are in the [Paths] section, as follows: (1) WinDir=C:\WINDOWS – this line is a path statement that de­fines the location of the Windows 95 parent directory. (2) WinBootDir=C:\WINDOWS – this line shows the path for the Windows 95 startup files. (3) HostWinBootDrv=C – this line defines the location of the boot drive root directory. These options are there for multiple HDD systems. MSDOS.SYS is fairly powerful so be careful as a wrong set­ting can cause your machine to hang. That’s why it’s Fig.2: Options For MSDOS.SYS Option Default What It Does BootDelay =2 Initial startup delay (seconds) BootGUI =1 Automatic Windows 95 startup. Set this value to 0 to boot to the command prompt. BootKeys =1 Enables startup keys F4, F5, F6, F8. Changing this value to 0 overrides the BootDelay setting. BootMenu =0 Hides startup menu (press F8 to display). Change to 1 to automatically see the menu without having to press F8. BootMenuDefault =1 Sets the default (highlighted) item on the startup menu (see Note 1). BootMenuDelay =30 Delay (seconds) that the startup menu remains visible before running the default menu item (only if Boot­Menu=1). The value can be from 1-99 but a value of 4-7 seconds is usually suitable. BootMulti =0 Setting this value to 1 enables dual-boot capabili­ties. Press F4 to launch the previous version of MS-DOS or F8 to access the startup menu (see Note 3). BootWarn =1 Displays the safe mode startup warning & menu. BootWin =1 This line enables Windows 95 as the default operating system. Setting this value to 0 enables the previous operating system (eg, MS-DOS 6.x). Logo =1 Displays the animated logo as Windows 95 boots. Note 1: Menu option 3 is highlighted if a previous Windows 95 load failed. Note 2: The delay gives the user time to press the function key. The default is 0 if BootKeys=0. Note 3: If BootKeys=0, then setting BootMenu=1 and BootMulti=1 has no affect on the default action. Note 4: Network=1 must be present or Safe Mode with network sup­port doesn’t appear as option 4 on Startup Menu. important to make a backup before you start experimenting. Don’t forget to restore the attributes of the msdos.sys file after you have fin­ished (type attrib +r +h +s msdos. sys at the command prompt). The Registry Strictly speaking, Windows 95 does not need autoexec.bat, nor does it need config.sys. About the only time you require these two files is for some DOS-based programs. Windows 95 does, however, need the msdos.sys file discussed above so don’t delete it. The reason why you don’t normally require autoexec.bat or config.sys is because Windows 95 make extensive use of the Regis­try. The Registry has been around since Windows 3.x but, prior to Windows 95, was not used that much. The Registry is basically a unified database where Windows 95 keeps all its configuration information. And although it’s laid out in a logical fashion, September 1997  71 Fig.3: the Configuration Backup Utility comes on the Windows 95 CD ROM and is useful for making Registry backups. it can be rather difficult to understand its workings. Basically, the Registry is split up into six different areas called “Keys”. You can find the necessary information on these in the Windows 95 Resource Kit. This kit comes as a 1348-page book which also includes a CD-ROM. However, in you already own a copy of Windows 95 on CD, you already have an on-line version of the Resource Kit in the D:\Admin\ Reskit directory (assuming that D: is your CD-ROM drive). Fig.4: when the backup process is complete, the main dialog box lists the latest backup and any previous backups. The older backups can be deleted if you wish. Once you’ve learnt a little about the Registry you will want to delve deep into its bowels and see what you can find. But first, you’ll want to make a backup in case things go wrong. To do this, you can use Microsoft’s own Configuration Backup utility. This can be found on the Windows 95 CD at D:\ Other\Misc\Cfgback and the relevant executable is Cfgback.exe. There is no shortcut to this program in the Start menu but there’s nothing to stop you from copying the program to your hard disc and creating the Fig.5: this is the opening window that appears when you run the Registry Editor. Note that the Registry is divided into six different sections called “Keys”. 72  Silicon Chip relevant shortcut in your Start menu using the Explorer. In fact, this is a good idea because it’s handy to be able to make a quick backup on a regular basis, even if you’re not into Registry hacking. When you start this program, you basically follow the bouncing ball. The backup menu screen is shown in Fig.3. All you have to do is enter some information in the Selected Backup Name panel (eg, a name, the date or the current general setup of the computer) and then click the Backup button. You will be asked if you really want to back up the Regis­ try and then another dialog box will appear, informing you that the process may take a few minutes. When the backup is complete, the main dialog box will show the latest backup, along with any previous backups (Fig.4). You can select any of these older backups and delete them if you wish but don’t delete the latest backup. Now that the Registry has been backed up, you are ready to take a look at its contents. You do that by running the Registry Editor (ie, Reg­edit.exe) and you will find that this program is already on your HDD. To load the Registry Editor, click the Start button, then click the Run option and type C:\Windows\Regedit on the Open line. The Registry Editor will now open when you click OK (see Fig.5) and you’re ready to start exploring its contents. I don’t want to delve too deeply into Fig.6: the data in the Registry depends on the hardware and software in the computer. The data appears in the righthand pane and is accessed by clicking down through the folders in the lefthand pane. the Registry because it differs from one computer to another, depending on its hardware and software setup. However, the basic layout is always the same – your Registry will appear to look just like anybody else’s but the actual data shown in the righthand pane will be different (see Fig.6). Note that the Registry Editor can both export and import data which is handy when you’re fiddling with the unknown. This lets you export that part of the Registry you are play­ing with and, when you want it back the way it was, you can import it again. If you know what you are doing, you can also add new keys and data to the Registry. But be warned – the Registry Editor is a powerful tool, which means you can easily corrupt the Registry so that important settings are lost. If you do that, you will have to reinstall Windows 95 unless, of course, you have backed-up the Registry beforehand and can fully restore it. SC Making Registry Backups If you’re going to explore the Registry, it’s imperative that you make backups first. By itself, Windows 95 makes a reasonable job of backing up the two files that form the Registry –System.dat and User.dat. Each time Windows 95 successfully starts, it backs up the Regis­ try by copying System.dat and User. dat to Sys­ tem.da0 and User.da0 respectively. If Windows 95 refuses to restart after you have hacked the Registry, copying the two .da0 files over the current .dat files should fix the problem. Note that these are all read only, hidden, system files, so you will have to undo their attributes first before copying the .da0 files over the .dat files. That said, you still must make backups to protect you from Registry hacking disasters and two very worthwhile utilities for doing this are provided on the Windows 95 CD ROM. The first, Configuration Back­up (Cfgback.exe), was covered in the main article. The second is known as the Emergency Recovery utility (ERU.exe) and you’ll find it in the Other\Misc\ERU folder. As well as User.dat and System. dat, the Emergency Recovery Utility also backs up and restores other critical system files. As with Cfgback.exe, the ERU lets you back up to floppy discs so that you can restore things to working order again even if you can no longer start Windows. Tip: How To Rename The Recycle Bin You can rename anything that appears on your Desktop by right clicking the icon and then clicking Rename. This applies to everything except -– you guessed it – the Recycle Bin. If you've always wanted to change the name of the Recycle Bin, you have to hack the Registry. Launch the Registry Editor (click Start, click Run, type C:\Windows\Regedit and click OK). Now burrow down to HKEY_CLASSES_ROOT,CLSID, {645FF040-5081-101B-9F0800AA002F954E} and change the Default value from "Recycle Bin" to the name of your choice. Another (easier) way to change the name of the Recycle Bin is to use the Microsoft Power Toys. These can be downloaded from the Micro­ soft Web site and they are often also made available on the CD ROMs that are included with some popular computer magazines. We'll have more to say about the Microsoft Power Toys in next month's column. September 1997  73