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┌───────────────────────────────────────────────────────────┐ │ NTG Rev 5 FOSSIL Compatible Communications Driver │ │ Release 2.00 │ └───────────────────────────────────────────────────────────┘ 26th October, 1991 Copyright (C) 1991 Nikos Karasawidis and Nik The Greek's Drama BBS +30-521-37156 (USR/HST V.42Bis) +30-521-37278 (MICROCOM MNP-10) NTG is 'freely' available copyrighted software, and supplied no charge to system operators of (tm) and 'Othernet' public access amateur network systems. It is NOT available in this form for commercial use or use outside of amateur EMail systems. Please read the License details at the end of this document on contacting the author regarding commercial application of NTG and associated products. NTG Revision 5 FOSSIL Communications Driver Version 2.00 NTG is a FOSSIL compatible Communications driver, suitable for use with the following (among others) bulletin board and FidoNet(tm) mailer software: Fido v11,12 BinkleyTerm Opus-CBCS RemoteAccess Maximus CBCS QuickBBS TPBoard SEAdog D'Bridge FrontDoor It handles hardware specific aspects of communications, to enable the above applications to run in multiple environments which are supported by a FOSSIL compatible driver. NTG is designed for the IBM PC, XT, AT, AT/386 and PS/2 range under the MS-DOS operating system version 2.10 and above, OS/2 in 'DOS compatibility' mode and under PC-MOS/386. It may also be compatible with other environments which emulate MS-DOS. The term 'FOSSIL' is short for "Fido Opus SEAdog Standard Interface Layer". It is a generic hardware interface used mainly by bulletin board systems and compatible mail software which evolved from the efforts of Wynn Wagner, Bob Hartman and Vince Perriello. The current "Revision 5" standard makes it possible for a lot of software to run on a wide variety of hardware platforms capable of running MS-DOS but with distinct and incompatible hardware. NTG's main task is communications handling. It is a fully interrupt driven communications driver which effectively handles communications "in background", and continues to receive and transmit characters asynchronously with any program or application running. The application itself need not be concerned about the time critical aspects of communications, nor the capabilities, limitations or features of the hardware itself. These are all handled by NTG itself. NTG is one of many FOSSIL drivers available. NTG implements many features found in other(tm) FOSSIL drivers, sometimes in a slightly different way. Known differences will be highlighted. This package contains NTG.COM, with the driver itself being a TSR program (Terminate and Stay Resident) which may be loaded and unloaded, activated or made dormant "on-the-fly"; and also NTG.SYS, a device driver implementation loaded from CONFIG.SYS. This is not as 'flexible' as using NTG.COM, but in general conserves some memory and allows loading in some environments where the TSR implementation cannot be used. - 1 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 Some of NTG's unique and more interesting features are: o NTG has been built to handle up to 4 COM ports concurrently in up to 16 different configurations, o It has an "open architecture" which will allow is adaptation later in its development to support multiport shared interrupt and intelligent asynchronous IO boards, o It supports the 16550 USART in fully buffered mode, providing the capability of much higher baud rates, performance and significantly less CPU overhead especially in multitasking environments, o The driver is extremely FAST, optimised for speed, and takes up very little memory, o Incorporates an optional "diagnostic" mode, so you (the user) can inspect the state of the FOSSIL driver itself; assisting in debugging and optimisation of software being written to use FOSSIL calls, and in attempting to determine problems in software using a FOSSIL, such as a mailer, BBS or BBS 'door', o Has 'hooks' for an installable driver to support network and multitasking software, forcing ill- behaved processor intensive programs to give more of their time-slice to the system when inactive or when simply "polling" communications or keyboard functions for activity or status reports, o Allows 'fast' routing of screen output directly via the ANSI driver, making "FOSSIL" screen output calls significantly faster than going via DOS itself, o Allows for problems in some XT & AT BIOS' when 16550AN's are installed: very often a BIOS will not 'see' the communications chip during startup diagnostics - so NTG will force the BIOS to recognise it automatically, o Provides a full range of utility functions in the same .COM file, including built-in carrier watch, system reboot, lock baud rate and/or communications parameters and allowing some PC BIOS compatible non-FOSSIL aware software to take advantage of a interrupt driven communications, o Allows resizing of communications buffers and locking/unlocking of baud rates and other communications parameters "on-the-fly", o Provides a means of displaying the currently loaded driver's "status" and active parameters. - 2 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 NTG.COM is both a FOSSIL driver (TSR) and a utility which can manipulate the resident version of itself. On first successful loading, it will terminate and leave the driver portion of itself (only about 5K or so plus buffer requirements) resident, and allocate communication buffers for each of the enabled ports (typically using 14K for a one port install when 'diagnostics' mode is enabled). It then captures and utilises the system's INT 14H (communications services) vector and services requests for all FOSSIL and non-FOSSIL aware programs using the INT 14H interface. NTG will NEVER load itself more than once, unless within different tasks when using a multitasker, such as PC-MOS/386(tm), DESQview(tm), DoubleDOS(tm) or VM/386(tm). This documentation assumes a working knowledge of MS-DOS, and no effort is made to explain MS-DOS functions, commands or setup. Some familiarity with BBS or mail capable software and other FOSSIL drivers will definitely be an advantage, but not required. USING NTG When running NTG, avoid using any other software which purports to enhance communications products (such as 16550.EXE). These WILL NOT work, and could cause your system to crash or work unreliably. NTG already uses the 16550 and 16550AN to full advantage. Avoid loading DOS's MODE command with NTG. NTG is incompatible with it's communications handling - if loaded after NTG, then both may fail to operate reliably. Printer redirection is usually ok, provided MODE is loaded before NTG. If you need to set a COM port's baud rate (which is why MODE is most often used), then you can get NTG to do that by "locking" the baud rate (using NTG /L as documented below) which sets the COM port immediately to that rate. Remember to "unlock" the baud rate if not using a constant speed between computer and modem. NTG.COM would normally be loaded in your AUTOEXEC.BAT, and installed as part of your normal system startup. A typical command line might be: NTG /F [Loads NTG.COM with default settings and fast ANSI] NTG will respond with a short copyright notice and an indication that it has been successfully loaded. The number of ports installed for will also be shown. - 3 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 NTG.SYS must be loaded from CONFIG.SYS (and probably can be using QuarterDeck's DEVICE.COM under DESQview but I have only run it this way for short periods) using a "device" line, such as: device = C:\NTG.SYS /P2 /L0:19200,8N1 /F [Loads NTG.SYS for 2 ports, port 0 (COM1) locked at 19200 baud 8 data bits 1 stop bit normal parity, fast ANSI] A similar copyright message is displayed as an indication that the driver has been installed. If NTG encounters an error in the command line, the driver will NOT be installed. The device driver version displays the command line parameter in error. NTG has been successfully run loaded "high" above the 640K mark using both QuarterDeck's QEMM(tm) and Qualitas' 386^MAX(tm) 386 memory management products. It should be noted that there may be performance differences as a result of either 386i virtual mode switching or differences in hardware RAM access speeds between mother-board RAM and that used on an extended RAM card. You should test the results on your own hardware before deciding which method is better, since generalisations without considering all the factors involved can be misleading. Other enhanced memory products may or may not work, but I am either not familiar with them or do not know enough about them to comment. Since NTG.COM can be unloaded at any time (unless NTG considers it unsafe to do so for various reasons), you should be aware that doing so sometimes creates "holes" in memory. This is not a problem so far as MS-DOS or various applications running in it are concerned, but the effect of releasing more memory for DOS to use may be lost. This is almost always the case when unloaded from within a batch file: the memory freed will not be available until after the batch file terminates. If the desired effect is to "disable" NTG completely, refer to the /Q and /C command line switches below. This leaves NTG loaded, but provides a means of disabling the driver completely and forces use of the BIOS INT 14H functions or a previously installed driver. One note regarding PS/2 hardware and applications which use its specific INT 14H functions (though I haven't actually seen any). A PS/2's extended BIOS contains a superset of INT 14H services, which were designed after FOSSILs first become available for PC's. The additional services are NOT compatible with the extended functions supported by FOSSIL, and you should therefore either unload (/U) or deactivate (/Q) NTG prior running such software. - 4 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 DEFAULT SETTINGS By default, NTG uses 1K (1024 byte) communications buffers for both transmit and receive. This should be sufficient, if not excessive, for most applications. This may need to be varied for systems running at slow (less than 6MHZ) clock speeds, use modems with higher baud rates, make use of special modem technology, run under multitasking software or run on a network. Some applications (for example terminal emulation systems and bulletin boards) require more buffering because of the nature of how they communicate. The fast 'ANSI' output is DISabled by default. The option to use the faster output method will normally work well under standard MS-DOS, DESQview or most DOS-based environments. This will NOT work under PC-MOS/386 as it makes use of an undocumented MS-DOS feature not supported by that operating system. After installation (only the first successful invocation of NTG.COM actually loads the TSR portion), the FOSSIL driver's extended interrupt driven functions are inactive, and only the basic BIOS services are provided (by NTG). An application must specifically "initialise" a port for communications to make it become active and use the interrupt driven functions. When NTG is installed, it does a brief and simple hardware diagnostic to detect what communications ports are valid. If errors are found (most PC BIOS' miss detection of 16550 USARTS, cannot detect non-standard communications hardware and do not look for anything above COM2), the appropriate BIOS tables and hardware bits are patched. This means that if you install and use non-standard port and IRQ settings for a communications card, and tell NTG about these (via the NTGPORT utility) your BIOS will be changed to reflect this, allowing other BIOS-compatible programs to use the communications port (COM1 through COM4 only since the PC BIOS can only support up to 4 ports). COMMAND LINE OPTIONS Following is a list of command line options available in either or both NTG.COM and NTG.SYS. These allow "fine tuning", setup and utility functions. Command line switches can be given with a preceding dash (-) or forward slash (/). Some parameters show a colon separating the switch itself and a numeric parameter: this is optional, and is included only for readability. An equals (=) or comma (,) are NOT optional and must be included since these separate different parts of a command line switch. - 5 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 There are basically two "groups" of command line switches. The first are configuration switches, which affect the tuning, performance and behaviour of the communications driver. These can generally be combined on the same command line (and invocation) without problems. Exceptions (if any) are noted where relevant. The second group are "utility" functions. These switches are normally used EXCLUSIVELY of all other switches. That is, if you use them, they must appear SEPARATELY on a command line. The switches in this group are: /C Recapture INT 14H vector /B Reboot system unconditionally /S Display driver status /H Display help for command line switches /U Unload driver from memory /W Enable/disable carrier watch Remember that you can invoke NTG.COM multiple times with no risk in loading the communications driver portion more than once in any logical "task". All utilities relating to NTG.COM are contained within the same .COM file. The device driver version works a little differently. Its command line (specified in CONFIG.SYS) must contain only configuration items, since the utilities are not supported. These are contained within a separate executable called NTGHELP.COM, and have a similar - if not identical - syntax to the utility functions in the .COM version. Any differences are noted below. ~~~ /T Set Transmit buffer size Available in .SYS and .COM versions eg. /T:512 Sets 512 byte transmit buffers The default transmit buffer size is 1024 bytes. Since file transfers are "transmitter driven" so far as speed is concerned, this should be large enough to service the interrupt driven transmitter without it "waiting" to be filled by the application. These should be increased in size where multitaskers, networks or faster baud rates are being used. - 6 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 /R Set Receive buffer size Available in .SYS and .COM versions eg. /R:2048 Sets RX buffer size of 2048 (2K) bytes The default RX (receive) buffer size is 1K, or 1024 bytes. In practice, only a portion of this is actually used on a constant basis, but this will be dependant on how fast an application can service the buffer (and keep it empty). Buffer sizes CAN be changed "on-the-fly". But at no time can both the receive and transmit buffers be increased in size beyond the combined amount when first installed. For example, if NTG was installed with 2K transmit and 4K receive buffers, only 6K is available to each port in total. Combined buffer size cannot exceed that 6K. An attempt to exceed this amount will result in an error. Changing buffer sizes whilst communications tasks are active will be disallowed. When modifying the buffer sizes, it is advisable to first specify the one which is to "shrink" in size, before the one which will "grow". For example, if 1K buffers were active (with a total of 2K available), and you wished to change these to .5K receive and 1.5K transmit: NTG /T1536 /R512 would result in an error (Maximum buffer size exceeded). The result could be achieved by changing the order of the command line arguments to: NTG /R512 /T1536 /P Enable concurrent ports Available in .SYS and .COM versions eg. /P:2 Enables two ports for use concurrently This sets the number of ports which can be active at the same time. Up to 4 ports can be used (in this current release), in up to 16 different configurations. By default, NTG enables one port for 'interrupt driven' use. This is the most memory conservative approach and fits the requirements of the majority of installations. The current version does not support shared port arrangements or multi-port 'intelligent' serial IO controllers. - 7 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 This switch does not determine WHICH ports will be valid, only HOW MANY can run FOSSIL driven at one time. The driver will support whichever port (0-15) the application selects. /L Lock ports baud rate and/or settings Available in .SYS and .COM versions eg. /L:0=19200 Locks baud rate on port 0 (COM1) to 19200 /L:1=38400,8N1 Locks port 1 (COM2) to 38400, and forces 8 data bits, no parity and 1 stop bit. /L:0=0,7E1 Unlocks port 0 (COM1) if previously locked, or leaves it 'floating' if not, then forces 7 data bits, even parity and 1 stop bit. The baud rate given must be valid for a standard FOSSIL driver, and can be one of 0 (unlock) 300, 600, 1200, 2400, 4800, 9600, 19200 or 38400. High speed modems locked at a baud rate of 9600 or above also have CTS/RTS hand-shaking forced since these use the modem's internal buffering which make use of CTS/RTS flow control. A baud rate specification of zero "unlocks" the baud rate and resets handshaking to default (whatever the application sets). When using this switch, your modem MUST support a constant modem to computer speed, otherwise any baud rate change requested by an application will be ignored, resulting in an incorrect setting between your system and remote. The result will normally be garbled input and output. When the baud rate is locked, the port's baud rate is set IMMEDIATELY. The baud rate is maintained at the locked rate even though FOSSIL is not active - applications making use of BIOS calls to change baud rate will not succeed. This allows non-FOSSIL aware applications to be run without fear of the baud rate being changed even though these do not explicitly support higher baud rates. /F Enables/disable 'fast' screen writes Available in .SYS and .COM versions eg. /F+ Enables 'fast' screen writes /F- Disables 'fast' screen writes - 8 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 This switch is used for versions of DOS which support faster character output via the undocumented INT 29H method (used to call the ANSI driver directly). To my knowledge, this will work on all DOS versions 2.00 through 4.01, but since it is "undocumented", there is no guarantee that it will work. This should NOT be enabled under PC-MOS/386 version 4.0 or below. /O Enable function 0x1c compatibility Available in .SYS and .COM versions eg. /O This switch is used to enable "compatible" operation of NTG in situations where either X00 or Opus!Com worked, but NTG doesn't. Due to a misunderstanding of the FOSSIL specification, X00 and Opus!Com return 0x1c (28) whenever the highest function number is requested by an application instead of 0x1b (27) as required the Revision 5 specification (FSC-0015). Several applications rely on the 'feature' of these drivers and require a 0x1c return to verify that the functions used by the application are present. At this time, a function 0x1c is not actually implemented by X00.SYS, Opus!Com or NTG. When given, this switch tells NTG to return 0x1c, and so allows applications relying on 0x1c to work with it. Typically, such programs will return with "FOSSIL not present" or "FOSSIL version too old" (or words to that effect) when NTG is loaded without using '/O'. /Z Sets 16550 FIFO size/trigger levels Available in .SYS and .COM versions eg. NTG /Z0 Enables full 16550 FIFO buffering (16/14) NTG /Z5 Disables 16550 FIFO buffers This switch provides the ability to 'fine tune' a system equipped with a National Semiconductor 16550AN UART. The UART is the device used in PC's for asynchronous communications handling, and the 16550AN is a superior form of these (as compared to an 8250 or 16450 with which it is pin-compatible), since it provides on-board FIFO (first-in first-out) buffers or queues for receiving and transmitting. - 9 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 Software must be built to specifically take advantage of this UART's features in order to gain any real benefit. Normally, the 16550's FIFO buffers are disabled on power-up, and remain that way unless specifically enabled. The software itself must service interrupts by emptying and filling "queues" rather than the normal single character receive and transmit holding registers. Having this ability to service multiple character requests in one hardware interrupt call makes it possible to SIGNIFICANTLY reduce interrupt service overhead and thus CPU usage on any machine. This has very obvious advantages when operating under a multitasker, on a network, concurrently with other heavily interrupt-driven devices or with modems or other communications devices running at high baud rates. The /Z switch takes a single digit parameter - a number between 0 and 5. This number affects the internal settings of both the UART itself (its internal 'trigger' levels, which define how "full" the FIFO's will be allowed to get before triggering an interrupt to the CPU for service) and how full NTG will let the transmit FIFO be queue on each transmit 'request'. Valid numeric parameters to the /Z switch are: /Z0 16 bytes 14 bytes (max) /Z1 14 bytes 14 bytes (max) /Z2 08 bytes 08 bytes /Z3 04 bytes 04 bytes /Z4 01 byte 01 byte /Z5 - FIFOs disabled - Where 16550AN's are not present, NTG automatically ignores this switch completely. The default value is '/Z0', which activates the full 16550AN capability. /M Enable/disable initialisation message Available in .SYS and .COM versions eg. /M+ Enable init message /M- Disables init message Normally the driver outputs a message when an applications initialises the driver for its use. This may be suppressed or reenabled by using this switch. /U Unload driver from memory Available in .COM version only eg. NTG /U Attempts unloading resident driver from memory - 10 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 This switch tells NTG.COM to unload itself from memory. This forces all ports to be deactivated (if any are active). This will fail if programs loaded after NTG have "captured" interrupt vectors which are used by NTG (and which NTG cannot restore as a result). In this case, NTG will not load, but will indicate this in an error message. You will have to either unload these later programs (such as FOSSIL appendages), or reboot your system. Since NTG.SYS is a device driver, it cannot be disabled or unloaded from memory. /Q Disable communications driver interface Available in .SYS and .COM versions eg. NTG /Q Disables resident driver This switch is normally given when NTG installs itself, and the effect is to "delay" capturing of the INT 14H vector until a '/C' command is issued. This may be useful if loading with a multitasker and using other incompatible communications drivers in other tasks. If issued while NTG is already loaded, the previously active INT 14H communications services vector is restored. NTG's extended FOSSIL services are effectively "dropped" out of the chain. /B System reboot eg. NTG /B0 Select default reboot method NTG /B Reboot (warm) This switch has two uses. When a digit is given after the 'B', the reboot method is selected. Only two values are valid 0 or 1. Method 0 selects a standard BIOS method of jumping to the system's reset vector. This should work with most DOS environments on a wide range of hardware, including PC/XT/AT and 386 compatibles. Method 1 makes use of the AT's keyboard reset line to cause a system reboot. It will work only on AT and 386AT systems. However, this method will work under some 386 specific software where the first method does not. (for example, PC-MOS/386). In short, it "plays rough". Some 386 machines and almost all PC/XT systems cannot and should not use this method. - 11 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 If no digit is given after the 'B', NTG proceeds to reboot the machine - unconditionally. /H or /? Display help information Available in .COM version only This switch displays information about command line switches and usage for those who don't believe that reading manuals is a very useful exercise. Pity they'll probably never discover or know about this switch unless told.... This switch much be used alone, and will not load NTG.COM into memory. The help screen displayed will look like: ■ Usage: NTG [options] · accepts / or - as switch character /U ∙ Uninstall (if already resident) /T=nnnn ∙ Set TX buffer size to <nnnn> (decimal) /R=nnnn ∙ Set RX buffer size to <nnnn> (decimal) /P=nn ∙ Enable nn concurrent ports (1-16 decimal) /D[=n+|-] ∙ Enable or install diagnostics panel /N ∙ Disable diagnostics panel (may be reenabled) /A=nn ∙ Set screen attribute for diagnostics window /Lp=n[,lps] ∙ Lock port <p> (0=COM1) baud rate to <n> (0=Unlock) Optional: l=Character length, p=Parity, s=Stop Bits /W=n+|- ∙ Enable(+)/disable(-) carrier watch on port <n> (0=COM1) /Q ∙ Prevent INT 14H capture (install) or release INT 14H /M+|- ∙ Enable(+)/disable(-) FOSSIL "init" message /I=n+|- ∙ Initialise(+)/deinitialise(-) FOSSIL on port <n> /F+|- ∙ Enable/dssable faster screen writes via ANSI driver /B[0|1] ∙ Select reboot method, or perform system reboot /Z[0-5] ∙ Sets 16550 FIFOs [0=Max(16) 4=Min(1) 5=Disabled] /O ∙ Enable function 0x1c "compatibility" /C ∙ Recapture INT 14H vector /S ∙ Display driver status /H or /? ∙ Display this help screen /C Recapture INT 14H vector Available in .COM version only eg. NTG /C Recapture INT 14H (must not be used with any other switches!) This forces NTG to takes a look at the current location of INT 14H and makes sure that it points into the resident portion of NTG. If not, it resets the INT 14H address to the correct location. This is most often necessary when using a multitasker - such as DESQview(tm) - which revectors the interrupt on - 12 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 loading. Since one standard method of detecting the presence of a FOSSIL driver is to examine memory shortly after the location pointed to by the INT 14H interrupt vector, the 'stealing' of the interrupt in this way causes many applications to fail to locate the FOSSIL driver. Applications which use the 'init signature' method of detecting a FOSSIL driver will not normally be affected by this behaviour, but there is a risk that whatever 'stole' the vector will unintentionally change CPU registers used by the application for the FOSSIL call, causing any number of complications (and probably a system crash!). Another use of this switch might be to enable toggling between two or more communications drivers which make use of INT 14H (such as packet radio communications drivers). '/Q' can be used to switch NTG "off" and restore a previous vector, and '/C' used to recapture it again for FOSSIL use. The following sequence is the suggested method of doing this: NTG /Q [other switches] (Install but don't vector INT 14H) <install other communications driver> NTG /C (Capture INT 14H saving previous vector) To use the secondary driver (which could even be another FOSSIL driver, but cannot be NTG), use "NTG /Q", and "NTG /C" to use NTG again. NOTE: This switch MUST NOT be combined with any others (since they will be ignored)! /W Enable/disable carrier watchdog eg. NTG /W0+ Enables carrier watchdog on port 0 (COM1) NTG /W1- Disables carrier watch on port 1 (COM2) This switch enables or disables carrier watch for a particular communications port. If carrier detect drops (the caller hangs up) while the watchdog function is active, the system will be rebooted. This feature is most often used with programs which are not "carrier smart" and do not monitor carrier detect - some of these were probably never intended to run with output directed to a communications port. If a caller hangs up while such a program requests input, it may be effectively "stuck", unable to continue until its input is satisfied. It is possible that this situation also presents a security risk. - 13 - /S Display NTG status Available in .COM version only eg. NTG /S Displays NTG's current status The resulting display will depend on the current state of the resident version of the driver in memory, but if loaded will normally look similar to: Driver Version: 2.00 Installed Ports Available: 1 Ports Active: 0 FOSSIL Revision: 5 TX Buffer Size: 2048 RX Buffer Size: 2048 Max Buffer Size: 4096 Diags Module: Inactive Init Message: Enabled ANSI Output: Fast Port Locked: 1 @ 19200 If the driver is not yet installed, only the first line will be shown, with the text "Not Installed". The diagnostics module (explained below) is one of "Active", "Inactive" (present but disabled) or "Not loaded". Any ports whose baud rate has been "locked" are listed sequentially. Note that port numbers are ZERO-BASED. Port 0 is what DOS refers to COM port 1 (ie. the device COM1), port 1 is COM2 etc. DOS does not define devices for ports above port 3, though NTG can utilise them. - 14 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 /D Enable/disable or install diagnostics module eg. NTG /D2+ On NTG install: Installs the diagnostics panel with a default 'refresh' rate of 2, and enabled (the '+' here is optional) Otherwise: Provided the diagnostics module has been installed, enables it and sets the 'refresh' rate to 2 NTG /D- Disables diagnostics screen updating (but does not deactivate them) This is an advanced option, useful for software development using FOSSIL calls as a means of viewing what the current state of the FOSSIL driver is in 'real time'. When enabled and a port is active for FOSSIL extended calls, a panel is continually refreshed on the screen during each timer tick which displays a summary of various FOSSIL driver states. Information for up to 4 ports can be displayed concurrently on the screen (thought this might get a bit messy!), overlaying anything currently displayed. By default, the "refresh rate" of the panel(s) is set to 0, which means it is refreshed EVERY timer tick, or at a rate of about 18.2 times per second. Refresh rates of 1 means every second tick, 2 every third, 3 every fourth, and so on. Since video memory is slower than normal RAM, slowing down the refresh rate will decrease the overall detrimental effect that diagnostics has on system performance. It should be noted that running diagnostics quite significantly impedes system performance and adds a great deal of CPU overhead in servicing what is effectively a "background" task. You can therefore only run diagnostics on a system equipped with a fast CPU (286 or above), running at lower baud rates and/or with a 16550AN UART. Some general 'minimal' guide-lines are: ■ 2400 baud or below ∙ 6-8MHZ 286 class ∙ 16450 UART or better ■ 9600 baud ∙ 10-16MHZ 286 class -or- ∙ 20MHZ 386 class ∙ 16550 UART ∙ 16450 UART ■ 19200 baud ∙ 16-20MHZ 286/386 class ∙ 16550AN UART It takes quite a bit of processing power to drive a 'background' routine to refresh video RAM (which is relatively slow) without impacting on system performance. - 15 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 If you are having any difficulties at all using the driver and have enabled the diagnostics panel, disable them immediately and try again. I have found this to be a major cause of problems in the past. This feature is officially 'not supported' under any conditions, and I certainly don't need to hear that it "does" or "doesn't" work on your system. Before ANY problem report is made for any reason whatsoever, please try whatever you are trying to achieve WITHOUT DIAGNOSTICS LOADED! Usual symptoms of the diagnostics panel impacting in a detrimental way on a system's ability to communicate are failed handshaking between mailers, poor resilience in file transfers when "task" switching under multitasking software, some spurious character loss from remote during terminal sessions, failure to initialise a modem and inability to detect incoming calls from a modem returning verbose response codes (amongst others...). When loaded (which must be done via the /D switch when NTG is initially installed), you can selectively enable or disable the diagnostics display from a keyboard "hot key". The window is in an initial "on" state, but can be toggled on or off by pressing LeftShift-Ctrl-5 (the '5' located on the numeric keypad). The 'refresh rate' can also be adjusted on-the-fly using LeftShift-Ctrl- Grey+ and LeftShift-Ctrl-Grey-. The panel itself can be shifted on the screen by holding down the LeftShift-Ctrl combination and pressing Up, Down, Left and Right arrow keys. Note that the background screen is NOT restored (since it is never saved). In summary: Left-Shift Action Numeric 5 Toggle panel "off" and "on" Grey+/Grey- Speed up/slow down panel refresh rate Arrow keys Move diagnostics panel on screen Note that these 'hot-keys' work, no matter if the panel is visible or not, but not if disabled using the /N switch. Toggling the panel "off" using LS-5 does not entirely defeat the CPU overhead required to service the panel. In that case, the background task is still active, and only the panel is not displayed. To entirely disable the diagnostics panel, either unload and reload NTG without the /D switch, or use "NTG /N" to effectively turn it off. The following diagram shows a typical diagnostics panel display, and explains the fields shown. All numeric values are hexadecimal (base 16). - 16 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 ┌── Port 0001 ┐ ─────── Port number, zero based (0=COM1) │ TX Cnt 0001 │ ─────── Chrs currently in transmit buffer │ TX Max 003F │ ─────── Maximum chrs found in transmit │ TX Bse 141E │ ] buffer (this is cleared whenever │ TX Top 241D │ ] ──┐ the port is initialised) │ TX Nxt 144A │ ] └── Transmit buffer pointers/limits │ TX End 1449 │ ] │ RX Cnt 0002 │ ─────── Chrs currently in receive buffer │ RX Max 0019 │ ─────── Maximum chrs found in receive │ RX Bse 241E │ ] buffered (cleared on init) │ RX Top 341D │ ] ───── Receive buffer pointers/limits │ RX Nxt 249A │ ] ┌─── Current flow control state │ RX End 249A │ ] │ highbyte=remote, lowbyte=local │ FlwFlg 0080 │ ───┘┌── Active flow control settings │ FlwCtl 0002 │ ────┘ highbyte=remote, lowbyte=local │ Status 6238 │ ─────── Current line/modem status │ FifoSz 0010 │ ─────── 16550AN FIFO buffer (TX) size │ Errors 0000 │ ─────── Number of FOSSIL errors registered │ ErrFun 0000 │ ─────── Function (AX value) of error call │ LastAX 0300 │ ─────── Last Int 14H function call (AX) │ Int14H 5F73 │ ─────── Accumulated Int 14H calls │ ISRInt 0D4F │ ─────── Accumulated hardware interrupts └──NTG─vX.XX──┘ If you want to load diagnostics but have them completely inactive by default, use the following batch file sequence: REM Load diagnostics module when installing NTG NTG -D <other switches ...> REM Immediately disable them NTG -N The option to load without screen refresh "/Dn-" still uses clock cycles: only the screen update is inhibited. The "/N" switch actually disables the background processing and will not cause any degradation in performance. "/D" can be used to reenable the module again. /N Disable diagnostics panel eg. NTG /N This switch disables output of diagnostic information to the screen, and also the background processing required to update it. - 17 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 /A Set diagnostics panel attribute eg. NTG /A=79 Causes the diagnostics panel to become intense white on red This allows the physical screen attribute to be set. By default, a colour screen uses dark blue on white, and a monochrome screen reverse video. /I Init/deinit FOSSIL enhanced functions eg. NTG /I0+ Initialise port 0 (COM1) for FOSSIL processing NTG /I1- Deinitialise port 1 (COM2) This provides the facility to force normally non-FOSSIL aware BIOS compatible programs to use the basic FOSSIL character input/output functions. This has specific advantages when running under a multitasker, since all input/output is from interrupt serviced buffers, and not directly polling the communications port for activity. Not all non-FOSSIL aware programs will be compatible with use of this option. Only strictly BIOS-compliant programs will benefit. Some program will have their own interrupt driven communications functions, and others will poll the port directly. Initialising the FOSSIL in this way MAY interfere with correct operation of these programs. GENERAL INFORMATION The following sections outline how best to utilise the driver and get the best performance from it on your hardware setup. INSTALLATION NTG.COM is usually installed in your AUTOEXEC.BAT or at some time before you load your communications software. Alternatively, MS-DOS 4.xx has an option to allow loading of some 'compatible' TSRs using an "install=" statement in your CONFIG.SYS. A major benefit of this is that NTG can be loaded before any environment variables are set, and so takes up the absolute minimum of RAM. However, as with the device driver when loaded from CONFIG.SYS, NTG.COM cannot be unloaded from memory using the "/U" option. - 18 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 ERRORLEVELS The following errorlevels are returned by NTG (this also documents some of the possible errors which can be returned): 0 No error - operation(s) successful 1 Status was requested and displayed 2 A FOSSIL driver other than NTG is present 3 Incompatible version of NTG is already loaded 4 Can't modify parameters with ports active 5 NTG is not yet resident or loaded 6 Not used 7 DOS memory allocation error - fatal abort 8 Invalid command line option 9 Can't unload - FOSSIL appendages are loaded 10 System reboot failure 11 Error enabling or disabling carrier watch 12 Unable to recapture INT 14H vector 13 Can't unload if installed from CONFIG.SYS 14 Maximum combined TX/RX buffer size exceeded 15 Can't disable/enable diags panel - not loaded 16 Unable to unload due to interrupt chaining 17 Problem initialising FOSSIL (with /I) MULTITASKERS Prior versions of NTG directly supported various multitaskers by allowing for "poll" detection on status and character I/O calls made to the FOSSIL. When NTG sensed a task was "idle", it automatically gave time slices up during "polling" to other tasks in the system. This internal multitasker support has been removed from NTG.COM and NTG.SYS, and the /X switch is no longer implemented. However, the current version of NTG does have 'hooks' for an installable driver to link into NTG and carry out this task. This eliminates much of the unnecessary "baggage" suffered by users of NTG who do not need this feature. It also eliminates code made redundant by not having all multitasker time slice resident at once, irrespective of which specific multitasker is in use. Only that code which is actually used and plays a part in support of the multitasker itself is loaded. While this current release (2.00) is not accompanied by these drivers (which are now [October, 1991] in beta test), multitasking appendages for DESQview/TopView and PC-MOS/386 will soon be available. - 19 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 MEMORY NTG.COM is approximately 11K in size. It is made up of the following main parts: Description Size Used by Resident ------------------------------------------------------------- ISR Device Driver 0.5K Common 4 ports Yes INT 14H Despatcher 4.5K Common 4 ports Yes Diagnostics Model 1.0K Common 4 ports Optional Initialisation/Setup 1.0K Run time only Discarded Command line utility 4.0K Run time only Discarded ------------------------------------------------------------- What eventually remains resident depends upon what command line options are used. Initial overhead is about 5K for the ISR and despatcher. If diagnostics are used (rarely), then add 1K. Add to this, the sum of the transmit and receive buffers times the number of communications ports selected. THE DIAGNOSTICS PANEL The ability to view the state of the FOSSIL driver is very useful when developing software utilising FOSSIL calls. It can also be an invaluable aid in "tuning" the driver to your machine. Memory is precious - especially in a multitasking environment, and most of the time, the standard 1K transmit and receive buffers are far too much to allocate. This can only be empirically tested. Instead of "guessing" and using trial and error to see how well the driver performs, it is much better to enable the diagnostics window. This provides a 'snapshot' of the driver 18.2 times per second (each clock tick). Particular fields to look at are: "TX Cnt" Indicates how full the transmit buffer is in bytes. "TX Max" This is the current 'maximum' count if characters in the transmit buffer detected by the diagnostics routine (it views the driver in 'snapshots' so cannot be completely accurate. "RX Cnt" Indicates how full the receive buffer is in bytes. "RX Max" Maximum count of characters in the receive buffer (see TX Max). - 20 - NTG Revision 5 FOSSIL Communications Driver Version 2.00 "Int14h" Particularly useful for monitoring program activity. This counter ticks over every time the running application requests a FOSSIL service. "Errors" Locates possible problems in the program you are running. Any time the program makes an "illegal" call (usually incorrect register values). The last FOSSIL function code invoked which triggered the error will be displayed next to "ErrFun". By observation, it is possible to calculate the optimum size for both receive and transmit buffers. 16550 USART SUPPORT NTG fully supports the 16550 USART in buffered mode. Using the /Z command line switch, you can decrease the amount of FIFO buffering used, or disable the FIFO's completely. This option has been included for "compatibility" reasons. Previous releases of NTG used the equivalent of "/Z2" buffering, whereas this release defaults to full use of the FIFO queues. If you have problems using the default "/Z0" setting, try reducing first to "/Z1", then "/Z2" or lower, and once you've found a setting that works, please contact me (I'm interested in know what sort of setup this DOESN'T work on). - End - - 25 -