Questions tagged [apple-ii]
The Apple II series of personal computers and related software and hardware. Use [apple-iigs] for the Apple IIgs in particular, or [apple] for Apple hardware in general.
204
questions
4
votes
3answers
161 views
Apple II: ProDOS, zero length prefix and MLI calls
I have a simple program on my Apple IIc written in assembly language. It starts by getting a filename from the user (just the file name, not the full path), then it opens the corresponding file with a ...
5
votes
2answers
559 views
What is the reason of the particular range of the last 4K block of memory selection in Apple II
Following my previous question on Identifying the functionality of the memory select in Apple II and now that I know that the memory select device is simply an interconnection block. Searching for ...
6
votes
2answers
467 views
Identifying the functionality of the memory select IC in Apple II
Three are ICs labeled memory select used in Apple II.
One to apply A6 on the three banks of RAM ICs.
One to generate /RAM_SEL applying the latched RAM output to the data bus.
And one to apply /CAS on ...
3
votes
2answers
204 views
Did any 5.25" floppy drives not based on the Apple Disk II offer quarter-track control
Unlike many drives, the Apple Disk II has inputs that control the individual head stepper coils. These are commonly described as advancing by half-tracks, since advancing a full track requires ...
2
votes
0answers
99 views
Apple II DMA daisy chain also used to arbitrate /INH?
On the Apple II series of computers, peripheral cards contend for bus mastership through a priority daisy-chain system. A peripheral card is only allowed to perform DMA if its DMA_IN line is at logic ...
27
votes
17answers
6k views
How much did the first hard drives for PCs cost?
I would like to know how much early PC hard drives cost but have only been aable to find adjacent or unsourced data.
According to the Centre for Computing History:
The "IBM 5161 Expansion ...
8
votes
1answer
931 views
Why does the Applesoft BASIC have shapes?
Why did Apple include shapes in Applesoft BASIC? There are no sprites on the Apple II, but shapes provide a simple vector drawing tool. As graphics go the shapes are kind of an odd duck, they provide ...
2
votes
1answer
224 views
Was the ProDOS beep part of the kernel or just a commonly duplicated piece of code?
On the Apple II, system beeps were typically just the 'Control-G' beep noise. However, many ProDOS-based applications from Apple Computer abandoned the firmware-based beep routine and instead used a ...
5
votes
2answers
243 views
What were the alternative graphic cards for the Apple II?
In this question, it's mentioned the Apple II's slot 7 was used by third party graphics cards. Is there any documentation on those? What were those cards and what were their capabilities?
2
votes
1answer
160 views
How did VisiCalc decide how many decimal places to display?
VisiCalc represented numbers in BCD to be able to handle decimals precisely. But how did it decide how many decimal places to display?
In some screenshots like https://www.researchgate.net/figure/A-...
9
votes
3answers
2k views
Algorithm for Apple IIe and Apple IIgs boot/start beep
What is algorithms use for boot/start sound (when turn on computer) in Apple IIe and Apple IIgs? I can't find information about Apple boot sound algorithms or where in computer ROM store either ...
5
votes
1answer
121 views
What are the HIFI and MUSIC modes of the RocketChip?
One of the CPU accelerators for the Apple II series is the RocketChip, which came in 5MHz and 10MHz versions. It came with a floppy disk that contained a number of utilities for manipulating the ...
0
votes
3answers
206 views
I need to find a controller card for an apple II 5.25 inch floppy drive, the 20 pin connector wont work on the 34 pin controller card i have
I cant find any adapters or secondary connectors, can anybody get me a link to a working floppy controller card that works or possibly a connector that goes from 20 pin male to 34 pin female? i have ...
1
vote
0answers
104 views
Frozen horizontal width coil in old CRT monitor
I have an old Apple IIe CRT monitor which could use a small horizontal width adjustment. Unfortunately, as I try to rotate the hex key in the coil with a CRT adjustment tool, it doesn't want to move. ...
1
vote
1answer
93 views
How many different standard boot sectors are there for Apple II DOS 3.3?
When formatting a blank 5¼ disk on an 8-bit Apple II using the INIT command, was there only ever one variation of the boot sector code that was written, or was it updated from time to time over the ...
4
votes
1answer
117 views
Determining which sectors in an Apple II floppy disk/image are used when the boot sector declares more than 1 sectors
The Apple II disk bootstrap process looks at the first byte of track zero sector zero to see how many sectors long the bootstrap code will be. It then loads these sectors at location 0x0800 and jumps ...
2
votes
2answers
155 views
How can the composite out of an Apple II be disabled?
The PC Transporter provides composite out via a cable run to the internal video header of the Apple II. In order to do this, I assume it has to disable the sync and colorburst generators so the Apple ...
2
votes
1answer
99 views
Which Apple II emulators were the first ones each to use the .do and .po “dsk” floppy disk image file formats?
Apple II emulation must have started around 25 years ago but I can't seem to find a history of emulation of the platform.
There are several disk image file formats but for now I'm interested in the ...
3
votes
1answer
223 views
What bug in first version of game Karateka for Apple 2e cause this game reset in Apple 2c?
If I try to start the first version of the game Karateka for Apple IIe on an Apple IIc, the Apple IIc will restart after reading the game from disk after a few seconds. Later versions of Karateka for ...
2
votes
1answer
414 views
How do I read the position of an Apple II joystick?
Many games on the Apple II supported input from the keyboard, joystick, and Sirius Joyport. While reading the keyboard and Joyport are straightforward, getting the joystick's position is not.
How ...
3
votes
1answer
114 views
Converting Apple II ProDOS blocks to DOS tracks and sectors
The 8-bit Apple II had two disk operating systems with different disk access semantics.
DOS used tracks and sectors. A sector is 256 bytes.
ProDOS used blocks. A block is 512 bytes.
But mapping ...
7
votes
2answers
861 views
How can I programmatically determine whether an Apple II .dsk disk image is a DOS .do image or a ProDOS .po image?
I'm interested in working with the most common Apple II disk image file format, .dsk.
(I only programmed these machines briefly in Basic around 1979-81 and have not been in the emulator scene, so I'm ...
6
votes
2answers
206 views
How to get out of Apple IIe mode on Macintosh Color Classic?
I just picked-up a Macintosh Color Classic with an Apple IIe card. I've never used one of these before but was able to get it to enter into Apple IIe mode. However, I cannot seem to figure out how to ...
3
votes
1answer
112 views
How was the second bank of Apple IIc ROM accessed?
The original Apple IIc had a 27128 16 KB ROM mapped into the
$C100-$FFFF range (the $C000 page was decoded for I/O). According to
the Apple IIc Technical Reference Manual the ROMEN1*
and ROMEN2* ...
4
votes
2answers
524 views
How to get into Apple BASIC prompt on an Apple IIc?
I just picked up a used Apple IIc. For some reason all I get when I boot is Check Disk Drive on the screen, even with a bootable disk in the internal drive:
I cannot even get the system to read the ...
7
votes
2answers
390 views
How long should I expect the Apple IIc self test to run?
I purchased a vintage Apple IIc computer and I want to make sure there are no failing components. I booted up the computer while pressing both Apple keys (open and close) at the same time. The ...
3
votes
1answer
153 views
Please Identify this Apple II Diagnostic Message: “IOU FLAG E5: 1 2 3 4 8”
Does anybody know the meaning of this message from the Apple IIe diagnostic?
IOU FLAG E5: 1 2 3 4 8
What are addressing the 1 2 3 4 8?
I’m pretty sure that IOU is the I/O chip, E5 is the location ...
9
votes
1answer
282 views
6502 False Reads and Apple II I/O
The 6502 series of CPUs has an
interesting quirk:
indexed loads and stores may perform a "false read", reading from the
target address or a different address on a previous page. There are
situations, ...
13
votes
1answer
581 views
Odd tokenizing in Integer BASIC
While researching the underpinnings of Integer BASIC (IB), I came across an oddity I'm hoping someone can explain.
Unlike MS-derived systems, IB converted numeric constants to their 16-bit ...
3
votes
2answers
200 views
Why did the Apple Disk II version 3.3 change the boot protocol?
From what I understand, early versions of the Disk Controller II required that there never be two or more consecutive bit times without a phase transition (which would read as "0") but an upgrade to ...
7
votes
1answer
245 views
Did the Apple II Integer BASIC use SWEET16?
In the Byte magazine article that Woz wrote about the Apple II (Vol 2, No 5), on page 43's last paragraph he mentioned how SWEET16 was useful and he estimated that about 20% of the Integer BASIC code ...
7
votes
2answers
509 views
How do you use the INHIBIT pin on the Apple II bus?
Pin 32 of the Apple II bus is a signal called /INH (short for "INHIBIT"). Some of what I found online about using this pin for an Apple II expansion card suggests it was inconsistently implemented ...
4
votes
0answers
164 views
How can I connect a PIA or VIA chip to the Apple IIc?
I have an early Apple IIc, model A2S4000 with the 342-0272 motherboard
and ROM 255. (I am considering upgrading the ROM, perhaps with a
switch that would let me switch between different ROM versions.)
...
6
votes
2answers
504 views
Are there standalone emulators of Applesoft Basic?
My only retrocomputing desire is to program in Applesoft Basic and relive the Apple II days from the 1980's. Playing games is of no particular interest to me. I just want to use a keyboard, not a ...
6
votes
2answers
233 views
Why does _Beneath Apple DOS_ show FM encoding rather than GCR?
From the beginning in 1978 the Apple II floppy disk system used GCR
encoding to convert data bytes to sequences of binary values to
be written to the diskette: first 4-and-4 encoding (never released),
...
4
votes
1answer
386 views
Price of original Apple ][ in 1980?
Apple introduced the "new and improved" Apple ][ Plus in 1979, but continued to sell the original ][ until early 1981. I speculate that some customers must have chosen the original Apple ][ over the ...
3
votes
3answers
470 views
How to transfer the address of a data block into zero page using the Merlin 8 assembler on my Apple //e?
I've been fooling around with the Merlin 8 (v2.58) assembler on my Apple IIe and ran into a small snag.
Basically, I would like to load the address of a block of data into a two-byte pair in zero ...
3
votes
2answers
171 views
How exactly does the Apple II monitor set and use the “last opened” and “next changable” locations?
Chapter 3 of the Apple II Reference Manual describes the
machine-language Monitor. On page 41 it describes certain
remembered locations:
The Monitor remembers the addresses of up to five locations. ...
11
votes
2answers
811 views
Best learning path for Apple IIe assembly language [closed]
I have an emulator up and running and access to the asimov ftp site, and I want to learn how to program assembly language on the Apple IIe. What assembler should I use (Merlin? LISA?) and what book or ...
5
votes
2answers
441 views
Where did the “LEVI” file selector/runner for the Apple II DOS 3.3 come from?
There's a fairly common BASIC program for DOS 3.3 on the Apple II that clears the screen, prints a catalog of the disk, and allows you to select files by letter to run or do other operations on them. ...
2
votes
2answers
305 views
80s game about running and maintaining a power station
Way back in the late 80s there was a game that centered around maintaining and running a power station for the local town. It wasnt particually complex or graphic.. just fun. On the lhs of the screen ...
15
votes
1answer
2k views
Why did the Apple IIe use a 2 MHz-rated 6502, even though it ran at only 1 MHz?
The Apple IIe was designed to be timing-compatible with the Apple II+ so that timing-depndent software (such games and copy-protection systems) and hardware designed for the Apple II and II+ would, ...
3
votes
1answer
248 views
Is there any RAM disk software available for Apple II DOS 3.3?
I have an Apple IIc with 128 KB of RAM, about half of which goes unused. Since the IIc has only one drive, it would be convenient to use some of that unused RAM as a RAM disk. I know that this is ...
4
votes
1answer
438 views
Is it possible to detect Horizontal Blanking (HBL) on an Apple II
Is there a way to detect HBL and or VBL on an Apple II, and if yes, how it's done?
6
votes
3answers
790 views
How does the Apple II read lines for video display from the text-mode frame buffer?
(This question applies also to the low-resolution graphics video
buffer, since that uses the same frame buffer as text mode, just
displaying it differently.)
As described on page 1-12 et seq. of The ...
23
votes
4answers
5k views
What is DRAM refresh and why is the weird Apple II video memory layout affected by it?
I've roughly known the concept for years, but never really understood it. Back in the day, two types of RAM typically used in home computers: static and dynamic RAM. Static RAM (SRAM) was apparently ...
26
votes
3answers
3k views
What do the '80/40' and 'keyboard' buttons on my Apple IIc do?
Above the keyboard of my Apple IIc there are two buttons that say "80/40" and "Keyboard".
On my machine, they both kinda feel broken. When I press them, they recede into the case and remain there for ...
12
votes
2answers
1k views
How is the Apple II text flash mode timed?
On the Apple II, there are three 40 column text modes: normal (white on black), inverse (black on white) and flash. A text screen can contain a mix of text in all three of these modes.
Flash mode is ...
4
votes
4answers
1k views
Why use an ADC or SBC with immediate zero on a 6502?
I'm perusing the Apple I version of BASIC, later known as Integer BASIC on the II. In several places I see...
ADC #$00
or
SBC #$00
Unless I'm mistaken, these mean add/subtract zero. What ...
10
votes
4answers
3k views
Is it possible to swap the Apple IIc's monochrome CRT tube for a color one?
I just love the Snow White industrial design language of the Apple IIc, especially when paired with the Monitor IIc. It is a classic design that doesn't show its age. I've even recently seen them ...
