Night Owl 9

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Text File | 1993-04-05 | 24KB | 618 lines

CronJr ver 2.50 Requirements ------------ MS-DOS based machine running MS-DOS 3.30 or higher. MS-DOS versions below 3.30 may be used, but are not recommended, since they require CronJr to use more memory. Background ---------- The reason for designing CronJr was for lack of anything better in the MS-DOS world. Simple but powerful programs like cron (part of AT&T's Unix) or Sleeper (public domain for HP's MPE) are non existent for PC's. With more and more companies moving from mini-computers to PC based LANs, one of the many things that has been lost was the ability to schedule the nightly reporting and maintenance programs needed to keep a business working during the day. Sure, it's possible to just write a large batch file that will run all your programs one after another. That solution is fine if it meets your needs. But if you need programs to run at specific times, and especially if your business revolves around a LAN, then this product is for you. The solution ------------ There are 3 methods of scheduler implementation in a DOS environment. Method 1 Make a background RAM resident program that will pop up when it is time to run a task. Method 2 Make a foreground program that loads the task as a child process. Method 3 Make a transient program that is only in memory when it is needed. Therefore, all memory is available for the task. Page 1 Faults for method 1 -------------------- The last thing the world needs is another RAM resident program to eat up memory, steal clock cycles, and substitute custom interrupt vectors. Most LAN users already use 20-70k for their network shell, and even more if they are running a NETBIOS emulator. The way most resident schedulers work is to stuff the keyboard when it is time to execute a task. This method can be seen in various automatic tape backup programs. This method is unreliable since the assumption is made that the DOS prompt is available, the command line is clear, and the path is set. Faults for method 2 ------------------- This method requires too much memory. If you want to run a batch file then you have to load another version of COMMAND.COM on top of the parent scheduler. Why method 3 is so swell ------------------------ 1. It is so simple. It relies heavily on two simple operating system level batch files. 2. The scheduler is not in RAM while the task is running thus all memory is available to the task(*). * The dreaded asterisk - If you are using a DOS version below 3.3 then around 23k is lost because COMMAND.COM needs to be invoked a second time. It is strongly recommend that DOS 3.30 or above is used. How it works ------------ 1. The schedule file CronJr.SCH is created by you. It contains the timing parameters for the tasks to be executed. 2. The master batch file, CronJr.BAT, is loaded from the command line. That is your last intervention. 3. The work file, CronWk.BAT, is deleted by CronJr.BAT. 4. The scheduler program, Cron.EXE, is loaded and the schedule file CronJr.SCH is read. 5. When the time comes to execute a process Cron.EXE dumps its scheduling information to CronJr.JOB, writes the CronWk.BAT file and unloads from memory to return control to CronJr.BAT. Page 2 6. If CronJr.BAT can find CronWk.BAT then the CronWk.BAT work file is called/executed. 7. Upon completion of CronWk.BAT, control is returned to CronJr.BAT which then executes CronJr.BAT (thus ending the original CronJr.BAT execution) with the parameter RELOAD which is passed to Cron.EXE in step 4, which causes the file CronJr.JOB to be loaded rather than the file CronJr.SCH . Hard to follow? Try this one. It is the remedial version. CronJr.BAT -> Cron.EXE -> CronWk.BAT (YOUR TASK) ->CronJr.BAT A. B. C. A. Installation ------------ Create a directory for CronJr, any name will do, and copy the Cron.EXE, EditCron.EXE and TimeNow.EXE programs into the new directory. If you are going to use CronJr on a LAN with multiple machines running CronJr, then you must make a separate directory for each machine. Examples: C:\CRON\386 F:\BOB F:\ACCTNG\CRON Each directory must contain its own CronJr.SCH file and its own unique CronJr.BAT file. A path may be set to point to the location of Cron.EXE. To see a list of startup command line parameters type Cron without any parameters and all possible parameters will be shown. For each CronJr directory created, type Cron START at their respective DOS prompt. Such as: C:\CRON\386>cron start This will create the CronJr.BAT file which is specific to its home directory. If you type out the CronJr.BAT file you will see how this file is unique to its home directory. Use the EditCron program to create or modify the CronJr.SCH file. The EditCron utility is fairly straight forward to use. The keystrokes used for operation are listed on a command line on the bottom of the screen. The keys are <A>-Add , <D>-Delete, <Enter>-Edit, <Esc>-Exit, page up/down and up/down arrow. Page 3 The EditCron utility will help prevent easily made common mistakes, such as illegal scheduling times, misspelling of abbreviations for the days of the week, and most importantly of all, invalid drives, directories and program names. BE VERY CAREFULL when putting in hours. If you are spanning hours then you need to put different values into the hour fields, otherwise put the same value into both hour fields. You will notice that the hour fields default to 0 when adding new records. If you want something to run at the 9th hour then put the hours in as 9-9, not the default value of 9-0. If you put in 9-0 you are spanning the hours 9, 10, 11... 22, 23 and 0. After setting up the CronJr.SCH file, type CronJr to start the scheduler. Installation Options -------------------- There are additional startup parameters such as DISABLE, NOSAVER, LOG, Txx, and OS2 that can be used along with START. All installation options can be viewed by running Cron without any paramters. DISABLE - disables the F1-DOS Shell for additional network security. NOSAVER - turns off the screen saver. LOG - causes CronJr to make entries into the file called CronJr.LOG each time a job starts and stops. The TimeNow.EXE program must be accessable for the log to be created. OS2 - creates OS2 CMD files instead of BAT files. Txxx - T for Text, allows user defined screen saver text. Spanning Hours -------------- Spanning hours allows you specify a range of hours in that a task will run. Lets say you have an incremental task that runs every 15 minutes ( 15i ), but you only want it to run during the business hours 9am through 5pm. You would specify the hours as 9-16. Note that 16 is 16:00 which is 4pm. Spanned hours are inclusive. In addition to influencing incremental tasks, spanned hours also influence non-incremental tasks. The tasks will execute once every hour at the specified minute for the hours specified. Page 4 CronJr.SCH File Format ---------------------- In the event you choose to use your own text editor to modify the CronJr.SCH file, then make sure that it creates a flat ASCII file without tabs. Enter one task per line using the following format. Minute Hours Day_Of_Month Month Day_Of_Week Executable_&_Parms Example ------- 50 16 * * MoTuWeThFr f:\public\bin\killuser.EXE 0 17 * * MoTuWeThFr f:\mtn_tape\databack.bat 0 5 * * Mo g:\acctng\weekly.bat 0 1 1 * SuMoTuWeThFrSa G:\ACCTNG\MONTHEND.EXE 0 1 1 1 SuMoTuWeThFrSa G:\ACCTNG\YEARLY.EXE 49 16 * * MoTuWeThFr C:\FUNNY\GOHOME.EXE 2i * * * MoTuWeThFr F:\stream\kevin.bat 0 1i * * MoTuWeThFr q:\hourly\bak2work.exe 15 9-16 * * MoTuWeThFr c:\bin\chk_qtr.com 30 12 * * We nopath.com 6 30 * * Su u:\pali\t2tape.exe /a /optic --- ---- --- ----- -------------- ---------------------------- Min Hour DOM Month Day_Of_Week Executable_& Parms Field definitions ----------------- Minute......: the minute of the hour you want your job to execute, 0 through 59. Hours.......: the hour of the day in military time, 0 through 23. If you want to span hours, then you must separate hours with a dash "-" without any spaces between the hours and the dash. Day_Of_Month: the day of the month 1 through 31. Month.......: the month of the year 1 through 12. Day_Of_Week.: the day of the week, SU MO TU WE TH FR SA. Executable..: a DOS executable string, .BAT, .EXE, and .COM files with a maximum combined path of 64 characters. EXTENSIONS MUST BE USED! Parameters..: optional parameters to be passed to the executable. Maximum of 128 characters. Page 5 Wild cards and increments ------------------------- *: Execute on every occurrence. Not used by Day_Of_Week. Not recommended for use with Minute. i: Execute in increments. Only applies to minute and hour. The 7th line in the example shows 2i which means execute in 2 minute increments. In theory this task could be executed 30 times a hour. Obviously * must be used for every level after the first i . Combinations of i in the minute and hour are not allowed. Combinations of i and spanned hours are not allowed. If i is used with the hour, then the minute should be * , otherwise execution will occur in X hours + Y minutes increments. Launch time ----------- Task checking and launching occur on the 1st second of the minute or whenever the "E" key is pressed. Screen Saver ------------ The screen saver becomes active after 10 seconds of keyboard inactivity. The screen saver will always redraw the CronJr screen once the time of day second hits 50. The CronJr screen can be displayed by pressing any key, such as the space bar. The screen saver can be disabled by using the NOSAVER command when creating the CronJr.BAT file with the START command. The screen saver can be easily customized to display your company name rather than "CronJr". Use the "T" (Text) command when creating the CronJr.BAT file with the START command. An example would be: cron START tAcme To specify a name that incorporates spaces put the "T" command in quotes such as: cron START "tAcme Explosives" Page 6 OS2 CMD file support --------------------- DOS deals with BAT files and OS2 deals with CMD files. CronJr can be made to use CMD files instead of .BAT files by using the OS2 command when creating the CronJr.CMD file with the START command. This is a VERY MINOR OS2 support feature. CronJr is a native DOS program and will run in a DOS window under OS2. Multitasking Operating Systems ------------------------------ CronJr has been tested and succesfully operates under the DesqView, Windows and OS2 environments. CronJr should run under other DOS multitaskers with no problem. Whether or not the programs that CronJr will be running will work is another problem altogether. Software Updates ---------------- Whenever you receive a CronJr update, always make a backup of all the files used by your current version of CronJr. Once you have backed up your files, delete or rename your Cron.EXE and CronJr.BAT files. Then copy the Cron.EXE program from the distribution disk to its target directory, then run Cron START, and any other parameters you so desire, to create the new CronJr.BAT file . EXTREMELY IMPORTANT ------------------- Be very careful when assigning launch times. A "feature" of CronJr is that it only launches tasks when Cron.EXE is resident. For example: You have 2 tasks set to execute at 19:00, each takes 20 minutes to run, and few tasks scheduled at 19:15. At 19:00 all 19:00 tasks are tagged for launching and the first task will be launched at 19:00. The 2nd task will be launched when Cron.EXE is reloaded and thus effectively launched at 19:20. Well it is now 19:40 and all tasks scheduled from 19:01 through 19:40 have missed their launch window. To prevent this from happening you should do the following. Schedule enough time between tasks. The 19:15 tasks in the example should have been set later to 20:00, or earlier to 19:00. Had they been scheduled at 19:00 then they would have run as part of the 19:00 launching. NOTE: Incremental launchings are exempt from this "feature" . Page 7 Proper scheduling ----------------- The best way to debug a faulty schedule is to run Cron.EXE instead of CronJr.BAT, and use the F1 key to exit to DOS. At the DOS prompt, change the time to T-MINUS 10 seconds to launch, such as 16:59:50 and then type EXIT to return to Cron.EXE . Inspect the contents of the CronWk.BAT file that is created, and then try to run it from the DOS prompt. There is no limit to the number of tasks you can put into the CronJr.SCH file. Common problems --------------- CronJr is running, and exits to DOS and does nothing. Problem: Running Cron instead of CronJr. Problem: Did not run Cron START in the execution directory. CronJr does not execute the programs listed in CronJr.SCH Problem: Could not find the programs. Need to specify the path in the CronJr.SCH file or set a DOS path. Problem: You did not specify .BAT, .CMD, .EXE, or .COM . Problem: Your scheduling parameters are incorrect. Most likely day_of_the_week not included. I.e. You are testing on Saturday a job you have set up to run Monday through Friday. CronJr plays this obnoxious fight song when it executes. Problem: Running the evaluation version. Licensing --------- Every purchaser of CronJr is granted a site license. One purchased copy of CronJr may be used by anyone employed by your company in the same building with no additional charges. Once you expand out of your building, you need to purchase another copy. Anomalies and Hints ------------------- There are two anomalies and one other point that you need to remember. Anomaly 1. CronJr only executes tasks on the 1st second of the minute. Example. If you had 3 tasks that each take 5 seconds to complete, and they are all scheduled to launch at 19:00 then they will be effectively launched at 19:00, 19:01 and 19:02. This feature was designed into the product. Page 8 Anomaly 2. Anomaly 2 arises out of anomaly 1. Example. If you set up a schedule that has 3 jobs, each set to run in increments of 10 minutes (10i * * * ...), you would assume that they would execute at the 10, 20, 30, 40, 50, 00 minute clock demarcations (assuming that the first launch minute was hh:00) and always launch one after the other. In reality this is not true. The first launching schedule would look like this. 1a. Job #1 launches at the first available minute. 2a. Job #2 launches at the first available minute after Job #1 completes. 3a. Job #3 launches at first available minute after Job #2 completes. The second and subsequent launchings might look like this. 1b. Job #1 launches 10 minutes after its's first launching or at the first available minute after Job #3 finishes or it may launch the first available minute after Job #1 if Job #1 takes more than 10 minutes. 2b. and 3b. Who knows. The best way to get around this confusion is to do one of three things. 1. Carefully plan and test your incremental launchings. 2. Rather than make your launchings incremental, make them minute specific. This may involve multiple line entries into the CronJr.SCH file for he same job at different times. 3. Make Jobs 1, 2 and 3 one job. The one thing you must remember. The CronJr.SCH file is only loaded at the initial load time. If you are running CronJr on a LAN and CronJr is running on a remote machine and you modify the remote machine's CronJr.SCH file, the remote CronJr will not reflect any of the changes made in the new CronJr.SCH file until the remote CronJr is aborted and reloaded. Network Security ---------------- Although disabling the F1-DOS Shell feature does enhance the security of the product, we do recommend that you take further steps to secure your system if your environment so dictates. Page 9 Many people use CronJr to backup their networks or route their E-mail, or do other tasks that require Supervisor or equivalent system access. It would be quite simple for someone to access the F1-DOS Shell and do what ever damage they want to do. It would also be simple for them to escape out of the CronJr program all together and get a DOS prompt. Our recommendations for enhanced network security are as follows. 1. If your system has a keyboard lock, use it and take the keys with you! 2. Lock the room that contains the CronJr machine. 3. Don't set up your CronJr machine as a Super User unless it is really needed. 4. Disable the F1-DOS Shell feature. 5. Modify the CronJr.BAT program to add a LOGOUT command just prior to the display of the "ECHO End CronJr Cycle" . This will ensure that once the Cron program is exited, the CronJr.BAT file will log itself out of the network prior to returning to a usable DOS prompt. 6. In addition to modifying the CronJr.BAT file to enable system logout, incorporate one of the Ctrl-C or Ctrl-Break handler programs into your system. This will prevent possible crooks from getting access to a "Terminate Batch Job" prompt prior to execution of the LOGOUT command. Do not rely on the SET BREAK OFF/ON command to be of any help. We have heard of a public domain system driver available on CIS called BREAK.SYS . The BREAK.SYS driver is supposed to prevent Ctrl-C or Ctrl-Break from interrupting a batch file. We have never tried these drivers, but we have been informed of these drivers by some of our customers. Getting legal ------------- Software Shorts hereby disclaims all warranties relating to this software, whether expressed or implied, including without limitation any implied warranties of merchantability or fitness for a particular purpose. Software Shorts will not be liable for any special, incidental, consequential, indirect or similar damages due to loss of data or any other reason, even if Software Shorts or an agent of Software Shorts has been advised of the possibility of such damages. Page 10 Software Shorts will not be liable for any damages due to malicious third party augmentation of the executable program, such as viruses. In no event shall Software Shorts's liability for any damages ever exceed the price paid for the license to use software, regardless of the form of the claim. The person using the software bears all risk as to the quality and performance of the software. The CronJr software is the copyrighted property of Software Shorts. Acknowledgements ---------------- Unix, cron and AT&T are registered trademarks of American Telephone and Telegraph Corporation. MPE and HP are copyrights of Hewlett Packard Company. Sleeper is available through INTEREX MS-DOS and Windows are registered trademarks of Microsoft Corporation. NetWare is a registered trademark of Novell Incorporated OS2 is registered trademark of International Business Machines. DesqView is a registered trademark of Quarterdeck Office Systems. Software Shorts is not affiliated with any of the above mentioned companies. Technical Support ----------------- Questions can be sent to CompuServe ID 70731,2507 or faxed to (714) 832-2391. One last word ------------- Software Shorts is dedicated to the creation and dissemination of short, single focus, utility programs for programmers. Hence the name Software Shorts ( no we don't make swimwear! ). Software Shorts utility programs may not be distributed by any individual or corporation as part of a commercial software release, or bundled with a turn key system unless the utility has been licensed to that individual or corporation for such distribution. The first version of CronJr was released in November of 1988. Page 11