Not all programs in YSFLIGHT.COM are open source. But, you can download some of the source code from the following URL.
I've flown to Seven Springs Ski Resort. Although I didn't ski since I was at 5,500ft in the air. (* There used to be an airport called Seven Springs (7SP) and you could fly into the ski resort in your general-aviation airplane and ski until several years ago.)
I've been writing my own MS-DOS V3.1 compatible DOS recently. The purpose is to replace MSDOS.SYS in one of the ROMs of FM TOWNS. In other retro PCs, some can run an emulator with a user-developed compatible ROM, or like MSX is an open standard, so you can run a retro game legally. As for FM TOWNS, the developer of UNZ emulator, Kasanova, has written an open system ROM. However, FM TOWNS has another ROM that has MSDOS.SYS, COMMAND.COM, and MSCDEX.EXE, which nobody was able to replace.
MSCDEX.EXE can be replaced with a compatible open-source module called SHSUCDX.EXE. I have been experimenting with it, and works with absolutely no problem. However, I still need MSDOS.SYS and COMMAND.COM which must be Version 3.1 equivalent. Actually to run SHSUCDX, it needs to identify itself as Version 3.3, but other functionalities can be Version 3.1 level.
Many of my friends asked if I can use FreeDOS. The conclusion is no. For some reason, the developer of FreeDOS mixed MSDOS.SYS, IO.SYS, and COMMAND.COM in one module. IO.SYS needs to be from FM TOWNS application disk or disc. Therefore FreeDOS cannot be used for a DOS variant like FM TOWNS. Software development is similar to chemistry. Once you mix chemicals, it is nearly impossible to separate them back to the original ingredients. Once you mix your software modules into one, it is very difficult to separate inter-dependent modules back to individual modules. I learned it hard way years ago.
If Microsoft opens MS-DOS Version 3.3, I wouldn't have to write my own, but Microsoft stopped short. They only opened up to MS-DOS Version 2.0. Better than nothing. At least I can read source code and compare disassembly to make sense of variables and flags. However, it is written pre-stoneage programming, or even before structured-programming paradigm. Hell of GOTOs. It is not practical to start from Ver 2.0 source code and morph it to Ver 3.1 equivalent. In fact, I cannot assemble it. I am suspecting some sources are missing. I'm wondering if anyone was successful in building MSDOS.SYS from the source code that Microsoft opened.
Unless the current (Japanese) copyright law changes wildly and it protects not only the developers, but also the software products, the situation stays the same. Strictly speaking you cannot run FM TOWNS emulator unless you own a FM TOWNS hardware. The number of working FM TOWNS hardware declines over time. If time t goes infinity, the number will become zero. Then nobody can run FM TOWNS emulator legally. Someone studying history of computer games 100 years from now won't be able to run FM TOWNS applications legally. I'd like to make sure such a person will not have a problem with copyright.
But, it will be too difficult if I start from zero because I cannot tell if I am writing correctly. So, I am writing it as a patch to existing MSDOS.SYS, and gradually taking over functions with my modules. It's like gradually eating original MSDOS.SYS. Kind of programming horror story :-) But, so far I successfully took over (ate) DOSINIT, PUTC(02h), FREAD(3Fh), FWRITE(40h), FCLOSE(3Eh), MALLOC(48h), FREE(49h), MREALLOC(4Ah), GETSYSVARS(52h). I am trying to take over FOPEN(3Dh), and it is tough as expected. I think I successfully took over a function (or procedure) to make up a full-path name with current directory and current drive taken into account (looks like called Fully-Qualified Filename in the DOS terminology). Then, I need to do media check, and then get to the directory sector. I think getting to the directory sector is very well defined, but I'm still vague about what to do with the media check, especially what I need to do if the media check failed. I'll see. I'm planning to make it open when it is able to boot into TOWNS OS without a single byte from original MSDOS.SYS. (Then I'll need to find an open COMMAND.COM somewhere or write my own.)
Johnson and Johnson's COVID vaccine is reportedly 66% effective with one shot.... Haven't we heard a similar number from Pfizer and Moderna? If I remember right (although I'm not good at remembering), Pfizer and Moderna vaccines are 60 to 70% effective with one shot, and 95% effective with two shots. Then, isn't Johnson and Johnson vaccine equally effective with two shots, but not just tested?
Actually,I really thought I was going to die last March. I had never experienced that bad health condition before. It took 3 months to fully recover. However, nobody knew much about COVID then. Only patients with cough and fever were tested for COVID, and I didn't meet the criteria. At this time, there is no way to tell if it was a COVID or something else.
It started in the first week of March. I had a very strange cough. I coughed like once an hour. But, just a single-shot cough. It never continued. Once I coughed, I didn't cough again for another hour or so.
Saturday 3/7. I felt sinus soreness. To be safe I skipped my bowling league. I took an over-the-counter cold medication before going to bed.
Sunday 3/8. My sinus soreness intensified. I stayed in bed for whole day.
Monday 3/9. I recovered as though I had nothing. I didn't even feel fatigue. I felt just normal. But, I stayed home and took a rest just in case. Luckily Carnegie Mellon was in the Spring break.
Tuesday 3/10. I felt really normal. My wife and I were going to the gym on Tuesdays. But, we started seeing COVID cases, and I had a cold-like symptom over the weekend. I asked our trainer if he was concerned, and he said no. So, we went to the gym as usual. And my trainer gave a pretty good (hard) exercise to me as usual. At that time, data coming out from Japan was suggesting very low fatality and severity. I was not expecting U.S. was going to mess up this much.
Wednesday 3/11. I experienced diarrhea and lost appetite. I got hungry, but after eating one or two bites, I felt full. I really thanked that CMU was in the Spring break. I was not in a condition that I could teach.
My body weight started diving down. I felt my stomach was digesting food extremely slowly. I think I lost 3kg (about 6lb) in a week. That was bad. If it continued 23 more weeks, my body weight would become zero. (Not really :-P) Beyond that, my mass will be negative. Does Theory of Relativity allow negative mass? (No worries...)
I was really lucky because CMU switched to online teaching after the Spring break. If my symptom was not from COVID, I was sure catching COVID on top of it was going to kill me.
Monday 3/16. Still I was feeling sick. Although I didn't have fever, not even elevated body temperature, I felt bad chill. I might have had problem breathing, but maybe not. It was so unclear symptom to me. I had to inhale strongly once every a few breathes. I was also getting a heart problem. My heart rate didn't go down below 70 even when I was lying down and doing nothing. Also the heart beat was so strong that my head was shaken on the pillow. I couldn't sleep. The best description of my condition was like after taking too much coffee. I felt I was going to faint at the beginning of my online lecture, but somehow I was able to get through.
Thursday 3/19. My wife's birthday. I pushed myself to get some Sushi dinner. As expected, my stomach broke again the next day.
Monday 3/23. I managed to finish my lecture without losing conscious. My body weight was still declining. I lost 10lb total from the beginning of the symptoms. The pace was slowing down though. I forced myself to eat some for dinner, but then I really felt sick. I really was worried my heart was going to stop. I visited ER. But, the doctor told that all the tests showed no problem in my heart. My SpO2 level was stable at 98% to 99%. I was feeling like dying, but my body didn't show any sign of problem.
Thursday 3/26. My PCP met with me. He told that it should be some virus infection, but it is unlikely to be COVID. He told me to believe in my own strength, and wait for a few more days.
Then I really started recovering in a few days. My fatigue didn't go away, but my heart-rate problem seemed to be gone.
Thursday 4/16. My heart-rate problem came back. The heart rate didn't go down. But, not as bad as in March. Just in case, I messaged my PCP, but he said if my condition is in general improving, it should go away.
I finally felt I fully recovered early June. It took whole three months.
If it was not COVID, what was it? I can think of two persons from whom I caught it. But, none of them didn't meet the testing criteria then. Therefore, they were not tested.
But, lately I saw an article that high heart rate while resting is one possible symptom of COVID. That was exactly my problem.
Well, because I lost my weight, I thought to keep that weight. But, it didn't work. I re-gained my weight. And, actually I was walking 10,000 steps per day, 5 miles indoor, spend 2500 Cal, but, it didn't work. I feel I started losing my muscle. And, I don't get sweat by doing it. And, maybe walking indoor without shoes on was not good for my knees. My right knee started hurting. I switched back to weight training and 1-hour exercise bike. FitBit is not smart enough to detect I am riding on an exercise bike.
Well, almost for sure this year is going to be a better year than last.
Let's hope the vaccines work as advertised and leave this pandemic behind soon!
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