Thanks, I never looked at bitrates or anything before I just made recordings and listened to them. Now I need to see what it's doing. I probably have some old editor somewhere but I just wanted to start in the right direction.
MD is essentially the same as CD quality except it's rewrite digital. MiniDisc was another one of those advanced technologies that got run over by direct to SD and other digital recording. That was fast? Sony doesn't make the little internal gumstick battery for my nice pocket recorder and hasn't for years, which means as a portable it's unsupported and dead. Kind of upsetting.
I don't have an MD but I guess it's the same as CD quality in terms of bit depth (16 bit) and sampling rate (44.1 KHz) but older models can only save as a compressed (lossy) format, while some newer models can save as PCM (lossless).
Regarding battery, if not genuine Sony, have you looked for replacement? this one?
www.amazon.com/Hitech-Prismatic-Gumstick-Portable-HHF-AZ01T/dp/B00067EBIE?tag=msp0-20Or you can always re-wire it yourself with an external battery... not very elegant but may work.
Yes there's a plug for external power, intended for transformer to put in 3v DC and there's an external battery clip. In their wisdom (usual Sony blackmail to use only their battery, memory Etc.) The internal battery must be charged and working for the Aux. battery to work. On mine even full, fresh charge, the Aux. battery doesn't work. So I can wire an external through the Power Plug. Point is, it's pocket size and I have a little lavalier stereo Mic. for live recording live music.

Time to upgrade to a digital pocket recorder that saves to SD and be done with this.
What started this all is a girl singer from one of the bands said she moved and, lost her cassette tape of the band. (we're talking tapes I made in about 1986) I was going to record to CD and dump to the computer. Then I found some MDs of "sound effects" so I thought, hey IS audio?

Meanwhile, got the tape player working last night, MD routed into the mixed, CD recorder working... This morning I was going to dump the cassettes to CD and have something to work with. Well, guess what? The cassette player from the old studio, is now deciding to be ornery and only play 5 seconds only rewind 5 seconds, some sensor or belt, broke overnight.
Curses Foiled Again! 
Plan "B" about to go into effect. Not as Hi-Fi but boom box with line out, into the MD recorder, and make masters from that. Same limits as CD, 74 minutes, while the original tapes are SA-90s.
Also no problem, because I have plenty of blank MDs and I don't use that recorder anymore. So making use of old technology, recent obsolete and some modern digital, I can make a cleaner mess of things.

Thanks for the help. I found Audacity on cnet free download.
http://download.cnet.com/1770-20_4-0.html?query=audio+editor&searchtype=downloads&rpp=10&filter=licenseName=Free|platform=Windows&filterName=licenseName=Free|platform=Windows&tag=pe-searchFacetsTile;navForm
Also something called Expstudio, which I may get just in case. I have some audio thing that I bought years ago, not installed on any recent computers. Magicx which I may be able to find. For now, Audacity and Thank You.
What I need is some simple A/D, RCA to USB device and I can eliminate all the intermediate steps. Probably should just look on eBay and order one from China...