ACAPsoft For software As Compact As Possible

Chop - File Splitter

Version 1.650 KB Download / 200 KB Installed
3 Feb 09

2K / XP / 03 / Vista

Return to the main page

Chop - File Splitter

Version 1.6
27 Jan 09


Program Info

This compact program is for splitting large files (including ones larger than 4 GB) down to the byte level for easier distribution. (Or if you are a spy, you can divide a file up and even semi-encrypt it for security reasons...) It's also useful for splitting up blocks of stream data. Using either a normal window or a wizard interface, files can be split by either the number of files that you want, the maximum file size, or you can use preset common sizes for EMailing, floppies, Zips, CDs, etc... The program can Chop and UnChop files in Wizard and normal interface, and supports file time and attributes preserving, CRC to detect file corruption, command line operation and even simple encryption. In addition, if size is an absolute priority and you do not need any of the more advanced features of Chop, you can instead set Chop to create a very small BAT file which will rebuild the file without Chop.


Command Line Operation
Programmers Notes
System Impact Statement
Licence and Registration


Run "Setup.exe" and follow the instructions. To remove Chop use the "Add/Remove Programs" option in the Control Panel. Chop stores all of its data files in the designated application data area, often "C:\Documents and Settings\USERNAME\Application Data\Sinner\Chop". If you would prefer that it saves in the same directory as Chop either run the program from a removable drive, such as a floppy of a USB drive, or delete the "DefSet.txt" file from the Chop directory.


There are two methods of operating Chop. The more simpler and linear method is the Wizard mode (press Wizard to start it) but the default method is the normal mode. The description below is more for the non-wizard mode, but it is still a useful reference for both methods.

Chopping Files

To Chop a file up, first select the file to be chopped by either browsing for it by pressing the "Choose" button, entering in the file manually or if not using the wizard, by dragging a file onto the Chop Window. Any file is acceptable providing it doesn't have the file extension of "chp". If using the manual method you must press "Check" when the file name entry is completed. Compressed files are probably the best option.

The next step is to decide how you want the file divided. Size is given priority over segment number, and it's important to note that some numbers are not possible for mathematical reasons. You can change the size/numbers using the slider bar or the up/down controls. There is also a combo box (or buttons in the Wizard) that allows you to quickly select some default sizes. These are;

Super Disk122000120
Zip 10010200099.6
Zip 250255000249
Zip 750766000750
CD 74660480 645
CD 80716800700
Flash 64 M6144060
Flash 128 M122880120
Flash 256 M245760240
Flash 512 M491520480
Flash 1 G972800950
Flash 2 G19660801920
Flash 4 G39321603840
Flash 8 G78643207680
Flash 16 G1572864015360
DVD SL43671424264
DVD DL79262527740

The flash sizes are deliberately under-rated as often the actual available space is only 90%-95% of rated capacity. You can also manually select any number of files between 1 and 9999, or file size up to 4 GB.

Next you select where the output files will go, the default being a "Named Folder" on the desktop. You can select it by using the "Choose" button, or by dragging a directory onto the "Chop" window. Ensure that "Multi-Removable" is selected in the Output destination combo box (or a checkbox with the Wizard) if you wish to output to a removable device, such as a floppy or a USB drive. This is so Chop knows to prompt you for media changing. (It is not automatically selected as it can be easier to Chop the file, and then put it on the media, especially if you do not have enough of them.) Otherwise you should select either "Named Folder" or "Folder". If "Named Folder" is selected than a directory will be created from the first eight letters of the source filename (E.g. If the file is called "HardCore.jpg" then a directory called "HardCore" will be the default.), otherwise the folder will be as selected. Change this if you prefer something else, but make sure that there is no new directory in your selection. (I.e. More than one new directory will NOT be created.)

Now you select the UnChopping method. Normally you should choose "Chop" unless space is critical. (Chop isn't that big!) Using "BAT" (a BAT file) loses a lot of the features of Chop (such as encryption, CRC, attribute and time preserving and comments) and it should not be used if there is spaces in the first four characters of the file name.

If you want you can add a comment as well that will be displayed prior to the file being UnChopped. Simply tick "Use" in the "Description" box and type it in. This can be a maximum of 300 characters.

You can also choose to encrypt the segments by ticking "Encrypt" and entering in an Encryption String in the edit box. It is extremely important to note that the file is Encrypted, not password locked. The difference being that there is no storing of the password anywhere - the whole file is mathematically scrambled based on what you enter. If you forget the Encryption String there is no easy way to decrypt the file. (I.e. We cannot help!) The encryption is 32 characters (If your string is too short then it is repeated.) and the comment is not Encrypted. (Thus you could make the comment a question to help you remember the Encryption String.) The encryption however is not very secure and is designed only to prevent casual viewing of any personal data.

Once you are ready, press the "Go Chop!" button and after finding the file CRC number (if CRC is enabled) the file will be split. If the output is in "Multi-Removable" mode then the program will pause between each segment. The program will then terminate. You can then distribute the segments in the way you planned. All of the files in the output directory ARE needed and the loss of ANY files will result in the inability to rebuild the original file. Therefore, it is advised to keep the original if the loss of the file will cause any major problem. (In other words, be careful, and if you lose your lives work do not blame us!) The files are named with a eight letter system, with the first four letters being the first four letters of the original file, and the last four being the file number, starting with "0001". For "BAT" UnChopping the will be in addition a BAT file that you can run to rebuild the file. (E.g. If you had a file called "HardCore.jpg" and made it into three parts, you would have three files "Hard0001.chp", "Hard0002.chp", "Hard0003.chp".)

As an additional feature, Chop can be set to be an On Top window. Simply Right Click on the title bar and select "On Top Toggle". This setting is remembered.

UnChopping files using Chop

Assemble all of the segments of the file into the same directory. Then, if you have associated the "chp" file type to Chop via the "Auto Run" button, double click any of the files and Chop will load. Alternatively, you can load Chop, and the select the file using the "Choose" button or by "dragging" any of the "chp" files.) The comment, if any, will be in the comment box and you can then select the directory that you want the file to be created in. If the file is encrypted then the "Encrypt" box will be checked and you should enter the Encryption String in the edit box. You can use floppies (or any other removable media), just be sure to put the first disk in first, and put in the correct files when asked. Last of all you press the "Go UnChop!" button and the original file is UnChopped into your chosen output folder.

UnChopping files using the UnChop.bat file

Assemble all of the segments of the file as well as the UnChop.bat file into the same directory. Then double click the UnChop.bat file and the original file is UnChopped into the same folder. Chop can UnChop these files as well (as well as any sequentially numbered group of files) if you lose the bat file.

Switching the Wizard On and Off

The Wizard is off by default, but if you want to use it then simply press "Wizard" and it will appear. Pressing "Close Wizard" reverts to the normal mode. Next time you start Chop the last interface used will load.


The CRC function is on by default and it simply makes a number out of the file to enable comparison between files. When it is enabled the file is checked before and after Chopping and Chop notifies you if there are any discrepancies. It is important to note that like all checksum methods this test does not prove that the file is the same, it simply reports in most cases any problems. It is possible, although extremely unlikely, for the file to be damaged and not detected. Chop can detect bit errors as well as translocation errors.

In addition to automatic testing Chop can be used to compare two files by pressing the manual "Check CRC" button. This button and the text box beside it have no effect on the saved CRC.


Chop needs a lot of physical memory to work fast. By default it will allocate enough memory to allow the entire segment to be loaded into memory, up to half the total physical memory. This can be changed to a maximum of all (Physical) or as much as needed (Maximum). Generally the "Half" setting is recommended, unless you have a lot of memory and are not running many other programs, The "Maximum" setting should be used with caution as it will often require Windows to expand the page file thus slowing down Chop more.

Command Line Operation

It is also possible to us Chop with command line functions. Three switches control the operation in this mode.

/iInput File
/oOutput directory
/qSuppress status messages


"Chop.exe" /i=c:\ /o=c:\Love /s=500

Which will chop "" to the directory "c:\Love" into 500K pieces named using the first four letters of the filename plus a number. (E.g. File0001.chp, File0002.chp, File0003.chp.)

"Chop.exe" /i=c:\File0001.chp /o=c:\Love

Which will reassemble "" to the directory "c:\Love" using the original filename from all of the segments that are in the same directory.

Programmers Notes

It may not seem like it, but this was a major re-design. Chop now divides down to the byte level, when before it only went down to kBytes. The file size selection process has also been changed. In particular, it used to try to average out the file size so the last file was roughly the same as the rest, but this wasn't what many users wanted. This version also implements the new code system. If you have already registered before you will EMail us to be issued a new code at no expense.

As always I am happy to hear any suggestions. Multiple directory support is an unlikely addition as it is easier to zip files first before Chopping, but if someone gives me a good reason... Size is not a huge factor for this program so any good ideas will probably happen.

Chop is programmed using MASM32 assembly language and has been tested on Win2000, WinXP and Vista.

System Impact Statement

We go to great lengths to reduce system impact, but we feel that it is still important to explain here what our programs do to your system. If you feel we are missing something, or you need further clarification, please contact us.

RegistryChop uses the registry if you associate Chop with chp files. The installer that comes with Chop uses the registry only for the required un-installation data, and not at all if you use the "Extract Only" mode.
System SettingsChop will associate itself with chp files on request.
FilesAll of its program files are stored in the installation directory, and all of its data files are stored in the designated application data area, often "C:\Documents and Settings\USERNAME\Application Data\Sinner\Chop". If you would prefer that it saves in the same directory as Chop either run the program from a removable drive, such as a floppy of a USB drive, or delete the "DefSet.txt" file from the Chop directory. These directories can be opened via the About box.
NetworkChop does not use the network. The installer does not access the internet in any way, but the ReadMe does have three graphic files that are stored on the internet. (They are not used as web-beacons, merely spacers and images for the payment processors.)
CPUChop can be CPU demanding while chopping.
MemoryBy default Chop will attempt to allocate enough memory to allow the entire segment to be loaded into memory, up to half the total physical memory. This can be set to take more, but it is not recommended.


1.00Initial Version
1.1xIncreased maximum file size, added pause, Split at Point function. removable media support, and more output options
1.20Encryption, improved folder selection, revised interface, ".chp" File association, BAT rebuilding, + more!
1.3xWizard, save settings and removal of Index file requirement, CRC
1.4Interface tweaks, command line control
1.54 GB+ support, Flexible memory usage, Interface tweaks
1.51Vista tweaks including association elevation, un-headered unchopping
1.6New code system, byte divisions, enhanced size selection, enhanced CRC

Licence and Registration

Permission is given to evaluate Chop for a period of 30 days. After this time you are required to either register or remove Chop . Permission is given for all forms of distribution, including CD compilations and Websites, providing the ZIP file is unaltered and it is made clear that Chop is a Shareware program and that registration is required for continued usage. Chop can be registered using PayPal, Reg.Net or Mail. For details on the terms of our licences and of our Buy-Three-Get-All policy please refer to the payment page.

Chop is a copyrighted work and thus permission is not given for you to decompile, disassemble, modify, translate, enhance or create derivative works from this program. If you feel that you need to do any of those actions, and that those rules do not apply to you, contact us first.

Single User
PayPal $8.00 USD
Reg.Net $8.50 USD Bulk deals are also available here. Buy Now at Reg.Net
Mail, Cash $8 USD or $10 AUDPostal details in About box
Mail, Australian Cheque $10 AUD
Mail, Non-Australian Cheque $10 USD or $20 AUD
PayPal $120 USD
Reg.Net $120 USD Buy Now at Reg.Net
Mail, Cash or Cheque $100 USD or $120 AUDPostal details in About box


ACAPsoft accepts no liability for this software to the maximum extent allowable by law. Installing this software is the decision of the installer, and signifies that you agree with this liability statement. Thus, any damage/loss caused by the use of this software is not in any way the responsibility of ACAPsoft. This includes, but is not limited to, physical damage and loss of income/time. In no event shall the maximum liability of ACAPsoft exceed the registration fee paid by the user, if any. Because some jurisdictions do not allow the exclusion or limitation of liability for consequential or incidental damages, in such jurisdictions the liability of ACAPsoft shall be limited to the extent permitted by law. If at any time you do not find these conditions agreeable you are required to remove this software.


Advice/insults (on the subject of the program, not the programmer) are always welcome. To help users keep up to date we send out newsletters whenever there is a major new version of Chop. To join this list simply send an EMail with "ChopADD" in the subject. To be removed from this list, write an EMail with "ChopREMOVE" in the subject. (ACAPsoft does not sell your EMail address or any other personal information to anyone.) In addition, we have a RSS feed that is updated whenever there is a new version of any program.

Support Forum
RSS Feed

© Copyright 2017 ACAPsoft. All Rights Reserved. • PrivacyContact