IRTF single-detector photometer computer upgrade (NewDAS)
Status: Operational in "MS-DOS Mode". December 8, 1997 (Revised 6/2/98)
Computer: Generic tower case PC running Windows 95
This document revised 6/23/99.
What is "MS-DOS mode"?
Details of Operation
When Things Go Wrong
Reliability problems and attained age have led to a decision by IRTF staff to upgrade the control computer and reduce the reliance on networked remote drives. The "NewDAS" software was coded for the DOS platform, using the multitasking DOS extension program Desqview as the user interface. The new computer replaces the Compaq Deskpro-20 which has been in use since the 1980's.
The Compaq is still available in its original form to be used as emergency backup. It only requires the transfer of external cables from the new computer to the old. The mouse cable is used only on the new computer; the Compaq doesn't use a mouse. The new computer runs Win95, which is much easier to manipulate with a mouse.
The latest NewDAS computer is a PC consisting of generic parts. It has 16 Mb RAM memory, an AMD 486 clone CPU, and a 409 Mb hard drive, all in a mini-tower case. The computer's operating platform is Windows 95, which provides much simpler and more reliable network connectivity through Samba on the Unix server, eliminating the necessity of fragile PC-NFS. There have been no changes to the NewDAS operating software; the whole package has been ported to the new computer. It now runs the original DesqView in Win95 "MS-DOS mode".
Remote directory trees on the server that were formerly accessed by the Compaq have been copied to the large local drive to make the system as independent of the network as possible. We need network connectivity just for the following:
- To transfer acquired data files to a workstation. (Default acquisition is to the local hard drive.) You can also transfer to a 3 1/2" floppy after the run is complete.
- It is still necessary to access a remote drive for off-line recompilation if code changes are made.
In case of network failure, the data files can accumulate on the local drive as long as necessary; there are hundreds of megabytes of available free storage. The data do not go out on the network in real time.
Note that communications to and from the telescope control system now occur directly from one of the local PC serial ports to serial port #3 on the LSI-11/23 TCS computer. This is the only communications mode on the Win95 PC. On the Compaq, one can set the DOS environment variable SERIAL=OFF to revert back to communicating via the network through the TCS comm link daemon on Stefan. Currently, SERIAL=ON is the default with the Compaq.
"MS-DOS mode": With Windows 95, there are two or three ways to get into DOS. "MS-DOS mode" is the equivalent of running DOS rather than Windows. This is the most secure way to run a DOS program. You can get into this mode by selecting a specially configured DOS icon (GODAS) on the Win95 desktop. In this mode, networking support is not provided. (The "Samba" PC networking server only works with Windows networking, not DOS as did the previous server, PC-NFS, which had unsatisfactory reliability.)
Unfortunately, it is necessary at this time to run in DOS Mode rather than in a DOS window under Win95. In a DOS window you get network connectivity, which gives you the choice of acquiring data into a data directory on the remote drive at the workstation, use of the laser printer, and other network conveniences. I found out, though, that the version of serial port support software we are using with NewDAS, "Greenleaf Comm Library" V2.2, was designed for DOS only and grabs the serial ports for itself. Under Win95, it crashes when the open() function executes to open a serial port. Windows doesn't permit programs to grab fundamental resources.
I purchased the latest version of the Greenleaf library, V5.2, which is designed to run under Windows. However, it won't compile with the old Microsoft compiler we used up to now. I appropriated a modern Borland C compiler, so all the pieces are here to upgrade NewDAS to run under Win95. This hasn't been done yet.
Boot the new PC by pressing the power on/off button on the PC's front panel. Windows 95 will eventually come up and ask for a password. At the end of the load, an application executes, Dimension 4, that synchronizes the PC clock with network time. The synchronization sometimes takes a few seconds. After it synchs, click "Exit" or wait for the 15-second automatic exit. Note that a mouse is necessary to work with Windows 95; one should be plugged into the PC monitor/keyboard switch box on the data acquisition table. Otherwise, I hope you remember the Windows hot keys for screen navigation, I don't. By the way, Dimension 4 is freeware on the net. I recommend it for keeping your networked PC on accurate time.
Double click the GODAS icon, which is an MS-DOS symbol. Windows goes away and a soft reboot occurs (after a bit of a wait) to a black MS-DOS screen that eventually produces the familiar GODAS request to strike any key. DesqView then comes up and you are asked as before for paths to a printer and a couple of routine files. LPT1: is the NEC dot matrix printer. After specifying the file names and paths as necessary, the introductory NewDAS screen is presented.
Proceed with your observations, exactly as done previously with the Compaq.
Transfer data: At the end of observing, or whenever desired, transfer your data files to the workstation herschel, or to a floppy (the default destination for the XFER transfer routine). To do this, you will need to exit DesqView back to Win95. On exit a warm reboot occurs, which takes about a minute and a half; eventually, you are presented with the green password screen, and a minute or so more gives you the Win95 desktop. Once Win95 is up, select the "XFER" file cabinet icon and an information screen presents you first with a selection of proper command string formats for what you want to do, then gives you a prompt to type the string.
[NOTE: The operation of the "XFER" program needs work to simplify it and make it more like what is actually needed.]
Here is the information for accessing the remote data file directory from the host and the PC:
- Herschel: The root of the remote directory tree corresponding to PC drive L: (the remote data destination drive) is /scrs1. You are free to establish your own directory tree for your data files under that, such as /scrs1/mydata.
- Win95: Click on the XFER icon (a file cabinet). Follow the instructions. Your data directory from this source is L:\mydata as an example, or A:\. Type EXIT after the operation is complete in order to terminate the MS-DOS window.
- Closing down: (suggested if at the end of a run of observations, otherwise leave NewDAS running)
Power down the computer directly if in DesqView. If instead you quit DesqView, a warm reboot to Win95 will immediately occur, which can be inconvenient (or desirable, depending on what you want to do). If you just wanted to quit and power off, but get the reboot, I suggest allowing Win95 to boot fully and then power it down in the usual way, selecting Start and then Shutdown. If you power down while Win95 is loading, you run the risk of corrupting things. Also, the next time you start up it will then automatically revert to "Safe Mode" since Win95 didn't load completely before. If this happens, allow "Safe Mode" to load completely, then select Start/Shutdown. When safe, power off momentarily and then on to bring up normal Win95. Note that Win95 takes forever to load after Safe Mode has been up. Just wait for it; it will eventually come up.
When Things Go Wrong:
A hang-up occurs while the Win95 logo is on screen during bootup; the traveling pattern on the bottom of the screen halts for more than 30 seconds, or a black text screen seems frozen (1 - 2 minutes, at least: allow plenty of time; it sometimes takes a long time to get past this point). Power off momentarily and then on again. Windows will boot up into a maintenance menu which includes "Safe Mode", which should be chosen. Allow it to come up completely in Safe Mode. Now, press Start/Shutdown and select "Restart the computer". The computer will eventually boot into Win95, after a longer than usual load time.
Note: When restarting after a crash do a power cycle, not a reset with the "Reset" button on the PC. I have found that cycling power is the only sure way to clear a hang-up.
Note: After being in "Safe Mode", the Win95 boot will hang in a text screen for 1 minute 10 seconds, much longer than expected. This is normal; just wait it out (sigh).
A red "COMPROC" (Communications process") error box referencing the TCS is displayed shortly after selecting a NewDAS operating mode (PHOTOMETRY for example). The communications link to the TCS is down, so the initialization failed. Exit the error box with the ESC key. Exit the data acquisition mode back to the introductory screen by selecting the QUIT menu item. Now you need to fix the comm link. Usually, in this case the TCS LSI-11/23 is down, or there are cabling/connector problems. If the TCS is not up, reboot it. In NewDAS, bring up the DesqView menu by pressing the ALT key. Select Open Window and type T3, which brings up a terminal emulation window, which will act like a terminal connected directly to the TCS line. Type a few "Enter" key strikes. You should get "-OK" responses. If so, the comm link is now up. Exit the terminal window with ALT and C for Close. Proceed as before.
If you don't get "-OK" responses from the TCS, check the cabling. Have the operator type AG-INIT, which resets the LSI-11/23 serial port. Reboot the Win95 PC. You will need to get "-OK" responses in the terminal window before the NewDAS will work.
A red "COMPROC" box referencing the TCS is displayed shortly after starting an integration. An error has occurred in the serial port protocol. Exit the error box with the ESC key. Additional error boxes will display every few seconds as integration proceeds. Stop integrating with the ABORT menu choice. You will have to exit the error boxes as they form, in order to do this. Eventually, integration will be stopped and no more error boxes show up.
This is probably caused by a hang in the serial port protocol at the TCS end. After the NewDAS activity is halted, have the operator type AG-INIT on the TCS control window. This command resets the TCS serial port and software. (The autoguider used to be connected to this port, thus the name.) Now, restart the data acquisition. If it still fails, exit the data acquisition back to the introductory screen and reboot the TCS. Restart data acquisition.
A red "COMPROC" box referencing a lock-in amplifier is displayed shortly after starting an integration. The lock-in amplifiers are probably powered off or are on "manual" selection instead of "remote".
A red "CAMPROC" (CAMAC process) error box is displayed. Most likely, a CAMAC crate is powered off, usually the one in the TCS control room. That crate is #2, and the crate out on the telescope is #1. Powering up the crate and restarting the software operation should fix this. If you can't clear this error, a CAMAC module or the interface in the PC may have failed. Try going to the backup computer (Compaq). The error box lists the various parameters of the CAMAC operation that failed. Write down these numbers for the day crew, which tell which CAMAC module failed.
How to switch to the backup computer (Compaq):
Power down. Unplug the cable connectors in the back of the Win95 machine. You will need a small flat blade screwdriver for the Digiboard connector. Note that there is a pigtail ribbon cable connector as well as a card end connector for Camac. Tuck the mouse cable (for COM1) somewhere where it will be easily found the next time that you install this computer.
Find the Compaq computer. It could be anywhere; it tends to scuttle off by itself and hide when nobody is looking. Set it up vertically in its space, bottom to the right (from the front). Plug in the cables (except for the mouse). Note the Camac ribbon cable pigtail coming out of the back of the computer; it has a black marking pen arrow mark. Connect the ribbon cable that has a matching arrow to this pigtail. The other ribbon cable goes to the card end connector. Plug it in the right way, and make sure you don't unseat the card when you plug it in. The keyboard cable plugs in to the front of the Compaq box, and the power to the very top back of the box.
How to switch back to the main computer (Win95 machine):
Power down. Unplug the cable connectors in the back of the Compaq and the keyboard cable from the front. You will need a small flat blade screwdriver for the Digiboard connector. Find the Win95 computer. It may be behind the door, or alongside the rack. Set it up in its space. Plug in the cables. Don't forget the mouse cable, which goes into the COM1 connector. Note the Camac ribbon cable pigtail coming out of the back of the computer; it has a black marking pen arrow mark. Connect the ribbon cable that has a matching arrow to this pigtail. The other ribbon cable goes to the card end connector. Plug it in the right way, and make sure you don't unseat the card when you plug it in. The keyboard cable plugs in to the hole about half way up the back on the left side. The notch on the connector goes to the right.
When to switch to the backup computer:
- Indications are that an interface card has failed in the on-line NewDAS computer. Successive reboots, power cycling, and TCS reboots (when relevant) don't work.
- When you need to communicate to the TCS through the network. Perhaps serial port #3 in the TCS has failed (try using port #1), or a cable/connector failure in the communications link is found. In this case, switch to the Compaq and, at the DOS prompt, type SET SERIAL=OFF. Then, type GODAS. Communications to the TCS will now occur via the network through the TCS communications daemon on stefan.
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