Unit: dos

[Aspect26]

Implement Dos unit:

• AddDisk - Add disk definition to list if drives (Unix only)
• DiskFree - Get free size on Disk.
• DiskSize - Get total size of disk.
• DosExitCode - Exit code of last executed program.
• DosVersion - Current OS version
• DTToUnixDate - Convert a DateTime to unix timestamp
• EnvCount - Return the number of environment variables
• EnvStr - Return environment variable by index
• Exec - Execute another program, and wait for it to finish.
• FExpand - Expand a relative path to an absolute path
• FindClose - Dispose resources allocated by a FindFirst/FindNext sequence.
• FindFirst - Start search for one or more files.
• FindNext - Find next matching file after FindFirst
• FSearch - Search a file in searchpath
• FSplit - Split a full-path filename in parts.
• GetCBreak - Get control-Break flag
• GetDate - Get the current date
• GetEnv - Get environment variable by name.
• GetFAttr - Get file attributes
• GetFTime - Get file last modification time.
• GetIntVec - Get interrupt vector
• GetLongName - Get the long filename of a DOS 8.3 filename.
• GetMsCount - Number of milliseconds since a starting point.
• GetShortName - Get the short (8.3) filename of a long filename.
• GetTime - Return the current time
• GetVerify - Get verify flag
• Intr - Execute interrupt
• Keep - Terminate and stay resident.
• MSDos - Execute MS-DOS system call
• PackTime - Pack DateTime value to a packed-time format.
• SetCBreak - Set Control-Break flag status
• SetDate - Set system date
• SetFAttr - Set file attributes
• SetFTime - Set file modification time.
• SetIntVec - Set interrupt vector
• SetTime - Set system time
• SetVerify - Set verify flag
• SwapVectors - Swap interrupt vectors
• UnixDateToDt - Convert a unix timestamp to a DateTime record
• UnpackTime - Unpack packed file time to a DateTime value
• weekday - Return the day of the week

[Aspect26]

Do not impement everything, find some good examples
TODO: exec(cmd, args), getDate, GetMsCount, GetTime,