You can mount a windows share on unix or on windows server you can use a unc path to write file
The process is as follows use the document upload control from content management toolkit and let the user upload all files, the document upload control binds to a ECMDocumentInfo list type, which contains the document urls for all the documents, you can retrieve the docID from the URL, then using Content Integration palette item and the docID get the contents of the document, the contents can be written to the file system using the following live connect code.
Example code is attached here https://bpm.tips/?qa=blob&qa_blobid=4491901628652884218
var byteValue = Packages.java.lang.String(tw.local.contentStream.content).getBytes();
var content64 = Packages.org.apache.commons.codec.binary.Base64.decodeBase64(byteValue);
var fileName="/tmp/" + tw.local.counter + "testfile.png"; // use the right file type of you can get the name from the properties also
var file = new Packages.java.io.File(fileName);
// if file doesnt exists, then create it
if (!file.exists()) {
file.createNewFile();
}
var fop = new Packages.java.io.FileOutputStream(file);
fop.write(content64);